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  1. #6776
    Guest Member S Landreth's Avatar
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    Zeke Hausfather - Its now official: 2023 was the warmest year on record in the JRA-55 dataset, at 1.43C above preindustrial levels.

    It beat the prior record set in 2016 by 0.14C, and continues a rapid warming trend thats seen global temperatures rise around 1C since 1970. https://twitter.com/hausfath/status/1742296413344850282


    Keep your friends close and your enemies closer.

  2. #6777
    Guest Member S Landreth's Avatar
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    • It's over: 2023 was Earth's hottest year, experts say.


    It's a moment scientists have warned about for months: Earth has just ended its warmest year since people began keeping records, and scientists say it may have been the warmest in 125,000 years.

    Even though the December data isn't yet official, the results were already "locked in" by mid-December, Gavin Schmidt, a scientist at the National Aeronautics and Space Administration, told USA TODAY.

    Given the six consecutive months of extremely warm temperatures, it was virtually impossible for December to be cold enough to alter the final results.

    "We are already beyond the point that any normal process would be able to keep 2023 from being the hottest year," Robert Rohde of Berkeley Earth, said in mid-December.

    Official reports from organizations such as the Copernicus Climate Change Service in Europe, and U.S. agencies such as NASA and the National Oceanic and Atmospheric Administration are set to make their "warmest year on record" announcements over the next couple of weeks.

    What's especially concerning, experts say, is that "the rate of warming over the past century has no precedent as far back as we are able to look, not only hundreds or thousands, but many millions of years," according to University of Pennsylvania meteorologist Michael Mann's book "Our Fragile Moment."

    "We are engaged in an unprecedented experiment with our planet," Mann told USA TODAY. "There is still time to prevent devastating climate consequences, but the window of opportunity is shrinking."

  3. #6778
    Guest Member S Landreth's Avatar
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    Zeke Hausfather - Global temperatures are now available from @CopernicusECMWF's ERA5 reanalysis product for 2023.

    They find it was the warmest year on record by a large margin, at 1.48C above preindustrial levels, higher than the 1.43C that JRA-55 reported earlier this week:


  4. #6779
    Guest Member S Landreth's Avatar
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    After months of expectation, it's official — 2023 will be the hottest year ever recorded. The European Union's Copernicus Climate Change Service announced the milestone after analyzing data that showed the world saw its warmest-ever November.

    Last month was roughly 1.75 degrees Celsius warmer than the pre-industrial average, Copernicus said, with an average surface air temperature of 14.22 degrees Celsius, or about 57.6 degrees Fahrenheit. And now, Copernicus says that for January to November 2023, global average temperatures were the highest on record — 1.46 degrees Celsius above the pre-industrial average.

    The boreal autumn, from September through November, was also the warmest as a whole "by a large margin," Copernicus said, with temperatures 0.88 degrees Celsius above average. In September, it reported that the summer of 2023 was the hottest on record.

    "2023 has now had six record breaking months and two record breaking seasons," Copernicus deputy director Samantha Burgess said. "The extraordinary global November temperatures, including two days warmer than 2ºC above preindustrial, mean that 2023 is the warmest year in recorded history."

    That difference between pre-industrial times and today puts the world dangerously close to crossing the 1.5 degrees Celsius global warming threshold that scientists have warned about for years. The continued warming means extreme weather events — which have already worsened — will become even more frequent and intense, exacerbating the damage and loss of life from droughts, flooding, hurricanes and wildfires.

    And it wasn't just the air that was warmer last month, but the water too.

    Copernicus said that the average sea surface temperature for ocean waters between 60ºN and 60ºS — roughly between the southern tip of Greenland to just below South America — was the highest on record, about 0.25 degrees Celsius warmer than the last record-breaking November, in 2015.

    Copernicus warned of this outcome last month, saying the warmest-year title was "virtually certain."

    The World Meteorological Organization, an agency of the United Nations, reiterated the warning at the U.N.'s COP28 climate summit just days ago, saying that the extreme conditions experienced this year have "left a trail of devastation and despair."

    The WMO also put out a report Tuesday saying that the rate of climate change has "surged alarmingly," with 2011 to 2020 being the warmest decade on record.


    ________




    Temperatures were so high in 2023 that a new colour could be needed to show it on the climate stripes image.

    The series of vertical coloured bars offers a visual representation of how our planet is progressively heating up.

    It was created by climate scientist Professor Ed Hawkins at the University of Reading, UK, in 2018.

    Ed Hawkins - 2023 was the warmest year on record globally by a large margin. Another dark red stripe gets added, though I think I need a new colour.
    #ShowYourStripes
    https://twitter.com/ed_hawkins/statu...29547790963190



  5. #6780
    Guest Member S Landreth's Avatar
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    __________




    For the last few years (since at least 2016), I’ve shared predictions for the next annual global mean surface air temperature (GMSAT) anomaly based on the long term trend and the state of ENSO at the start of the year. Generally speaking, this has been quite skillful compared to persistence or just the long term trend alone – the eventual anomaly was consistently within the predicted bounds. Until 2023.

    As described in my original post on 538, I take a loess smooth for the GISTEMP long term trend (using roughly 20 year smoothing) and add a term based on the linear regression of the beginning of the year Multivariate ENSO Index (MEI2) (similar to Nino34) to the detrended anomalies (not including some big volcanic years). This makes sense since, historically, the interannual variations in GMSAT were largest in the first half of the year and dominated by the phase of ENSO (El Niño or La Niña). This pattern was important for recent record or near-record years like 2016 or 2020 which started with El Niño, as well as below-trend years like 2017, 2021 etc. that started with La Niña. The development of the ENSO phase in the latter part of the year (which peaks around December/January) generally has less of an impact because of the lag of ~3 months or so of its affect on global temperatures.

    There are two main sources of uncertainty in this method, the variation of temperature not related to the prior ENSO, and the uncertainty in the DJF ENSO index from the Dec predictions. Thus the true prediction (made around Jan 1), is slightly more uncertain than the retrodiction (which knows the actual DJF ENSO value). As mentioned above, this technique has historically been quite skillful:




    Estimated from Jan-Nov data.

    The RMS forecast error (not including 2023), is 0.07ºC, compared to 0.10ºC for persistence or smoothed trends. This year however was noticeably warmer than the prediction or retrodiction based only on DJF ENSO at the beginning of the year (which you will recall was a slight La Niña), falling well above the 95% CI.




    This could be due to a real anomaly in the interannual variability that was outside the 95% expectation, a mis-specification in the statistical model (e.g. we could have included an autumnal ENSO state as an additional predictor, or taken predicted forcings (solar, aerosols, volcanoes) into account), or something extra that we just haven’t seen before.

    But how are we going to find out? What happens in 2024 will be important. Does it go back to being predictable based on ENSO (in which case 2024 is expected to just be a little warmer than 2023), or does the positive anomaly persist? We will also be seeing more comprehensive estimates of the impact of the Hunga-Tonga eruption, and also of the impacts of the decreases in marine shipping emissions. It might be that the initial estimates of their impacts were underestimated. We will also see more in depth explorations of the spring to fall anomalies in the North Atlantic/North Pacific which contributed strongly to the temperature changes, but aren’t obviously related to El Niño.

    If nothing else, 2023 reminds us that the climate system still has surprises for us, and that this would be a very bad time to our eyes off the ball.

    __________


    • Zeke Hausfather - Global temperatures in 2023 were really weird.


    For almost every other year we can pretty reliably predict temperatures (red dot and bars) based on the long term trend, the prior year, and the El Nino / La Nina conditions at the start. For 2023 this model completely breaks down: https://twitter.com/hausfath/status/1743398624103678083




  6. #6781
    Guest Member S Landreth's Avatar
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    Copernicus – December 2023 was the warmest December recorded




    2023 was the warmest year recorded





    Global Climate Highlights 2023


    __________




    “Astounding” ocean temperatures in 2023 supercharged “freak” weather around the world as the climate crisis continued to intensify, new data has revealed.

    The oceans absorb 90% of the heat trapped by the carbon emissions from the burning of fossil fuels, making it the clearest indicator of global heating. Record levels of heat were taken up by the oceans in 2023, scientists said, and the data showed that for the past decade the oceans have been hotter every year than the year before.

    The heat also led to record levels of stratification in the oceans, where warm water ponding on the surface reduces the mixing with deeper waters. This cuts the amount of oxygen in the oceans, threatening marine life, and also reduces the amount of carbon dioxide and heat the seas can take up in the future.

    Reliable ocean temperature measurements stretch back to 1940 but it is likely the oceans are now at their hottest for 1,000 years and heating faster than at any time in the past 2,000 years.

    The most common measure of the climate crisis – global average air temperature – was also driven up in 2023, by a huge margin. But air temperatures are more affected by natural climate variations, including the return last year of the warming El Niño phenomenon.







    “The ocean is the key to telling us what’s happening to the world and the data is painting a compelling picture of warming year after year after year,” said Prof John Abraham, at the University of St Thomas in Minnesota, part of the team that produced the new data.

    “We’re already facing the consequences and they will get far worse if we don’t take action,” he said. “But we can solve this problem today with wind, solar, hydro and energy conservation. Once people realise that, it’s very empowering. We can usher in the new energy economy of the future, saving money and the environment at the same time.”

    A separate report, by the consortium Global Water Monitor (GWM), found some of the worst disasters of 2023 were due to unusually strong cyclones bringing extreme rainfall to Mozambique and Malawi, Myanmar, Greece, Libya, New Zealand and Australia.

    New Record Ocean Temperatures and Related Climate Indicators in 2023 | Advances in Atmospheric Sciences - Ocean and Climate - Global Ocean Heat and Salt Content - Seasonal, Yearly, and Pentadal Fields

    Lijing Cheng: https://twitter.com/Lijing_Cheng/sta...72988466491537 - https://twitter.com/Lijing_Cheng/sta...73064341442912

    __________




    2023 “smashed” the record for the hottest year by a huge margin, providing “dramatic testimony” of how much warmer and more dangerous today’s climate is from the cooler one in which human civilisation developed.

    The planet was 1.48C hotter in 2023 compared with the period before the mass burning of fossil fuels ignited the climate crisis. The figure is very close to the 1.5C temperature target set by countries in Paris in 2015, although the global temperature would need to be consistently above 1.5C for the target to be considered broken.

    Scientists at the EU’s Copernicus Climate Change Service (CCCS) said it was likely the 1.5C mark will be passed for the first time in the next 12 months.

    The average temperature in 2023 was 0.17C higher than in 2016, the previous record year, marking a very large increase in climate terms. The primary cause of this increased global heating was continued record emissions of carbon dioxide, assisted by the return of the natural climate phenomenon El Niño.

    The high temperatures drove heatwaves, floods and wildfires, damaging lives and livelihoods across the world. Analysis showed some extreme weather, such as heatwaves in Europe and the US, would have been virtually impossible without human-caused global heating.

    The CCCS data also showed that 2023 was the first year on record when every day was at least 1C warmer than the 1850-1900 pre-industrial record. Almost half the days were 1.5C hotter and, for the first time, two days were more than 2C hotter. The higher temperatures increased from June, with September’s heat so far above previous averages that one scientist called it “gobsmackingly bananas”.

    Carlo Buontempo, a CCCS director, said: “The extremes we have observed over the last few months provide a dramatic testimony of how far we now are from the climate in which our civilisation developed.

    “This has profound consequences for the Paris agreement and all human endeavours. If we want to successfully manage our climate risk, we need to urgently decarbonise our economy whilst using climate data and knowledge to prepare for the future.”

  7. #6782
    Guest Member S Landreth's Avatar
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    Preview of this weekend’s update……


    Greenland Ice Sheet lost 20% more ice mass than thought, study says

    Scientists may have underestimated the amount of Greenland Ice Sheet melting since 1985 by as much as 20%, a new study found.

    Why it matters: Such an underestimate of Greenland ice mass loss indicates a heightened risk of shifts in ocean currents and global weather patterns, the study notes.


    • To date, melting of the Greenland Ice Sheet is the biggest contributor to global sea level rise.


    Zoom in: The study focuses on glacier calving retreat, which means ice lost at the edges where glaciers meet the sea.


    • According to the new research, published in the journal Nature, since 1985, the Greenland Ice Sheet has lost about 5,091 square kilometers (1,965 square miles) of area due to its retreating calving front, which amounts to about 1,034 gigatons of ice that has slid into the sea.
    • The study combines 236,328 manual and AI-generated observations of glacier terminus, or end, positions with a model to capture ice flow. The researchers used this to provide insights into the monthly aerial extents of the entire ice sheet between 1985 and 2022.


    Of note: Because much of this ice is already floating in the sea, its melt does not directly contribute to sea level rise, but it threatens to upend ocean currents.

    What they found: The data indicates that the rate of ice retreat stayed steady until the 1990s, with a faster rate of loss since 2000.


    • Every region of the ice sheet shows area and mass loss during the period.
    • The researchers used observations from 203 marine-terminating glaciers and four glaciers that end on land, which comprise 90% of the total mass of the ice sheet.
    • Only one glacier saw gains in mass during the period, and it was small compared to the losses elsewhere.


    The bottom line: "Nearly ever glacier in Greenland has retreated over the past few decades, and in a warmer world, we posit that the glaciers that are most sensitive to changes on seasonal timescales will show the greatest sensitivity to future climate change," the study finds.

    The intrigue: The two glaciers that have lost the most mass — Jakobshavn Isbrae near Ilulissat on the west coast and Zachariae Isstrom in northeastern Greenland — vary considerably throughout the seasons, influenced by ocean currents and water temperatures.


    • Scientists found that glaciers' seasonal variations is the best predictor of long-term mass loss.
    • "It is clear that a widespread forcing mechanism has touched nearly every glacier in Greenland over the past few decades and has most considerably affected the glaciers that show sensitivity to environmental change on seasonal timescales," the study states.
    • The study's authors claim they capture more than 1,000 gigatons of ice loss that has not been included in previous ice mass loss studies, in part because it can't be detected by satellites and other measuring technologies.


    Between the lines: The melting is having far-reaching effects, to which this new study calls attention.


    • With more freshwater going into the North Atlantic Ocean since 1985 than previously known, it could explain some of the weakening observed in the vital Atlantic Meridional Overturning Circulation (AMOC), part of which includes the Gulf Stream.


    • "There is some concern that any small source of freshwater may serve as a 'tipping point' that could trigger a full-scale collapse of the AMOC," the study warns, noting the widespread impacts that would have on weather patterns and food security.


    What they're saying: "We have known for a while that many of the models projecting ice-sheet evolution have difficulty in simulating the recent changes," climate scientist Richard B. Alley of Penn State told Axios via email. Alley was not involved in the new study.


    • "It has been less clear what parts of the data should be the target for improvements," he said, noting this new data set might indicate "a much better target" for testing models.
    • Ruth Mottram, a researcher at the Danish Meteorological Institute, who also was not part of the new study, said the techniques used in the study are novel.
    • "There is a huge amount of machine learning based insights coming into glaciology, and Earth science in general, and I think this is a nice demonstration of how we can use statistics on big, high quality datasets to really learn something about the world," she told Axios.


    As for the study's results, she said: "They show pretty convincingly that seasonal dynamics — that is, how far a glacier moves forward in winter and then calves back in summer, is the most important determinant on how much ice the glacier is losing over the study period," she said.


    • "Essentially, the more dynamic a glacier is on a seasonal timescale, the more sensitive it is to climate change."

  8. #6783
    Guest Member S Landreth's Avatar
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    NASA – December 2023 was the warmest December recorded




    NASA – 2023 was the warmest year recorded





    Five Factors to Explain the Record Heat in 2023

    NASA announced that 2023 was the hottest year on record, according to an analysis of annual global average temperatures by the Goddard Institute for Space Studies. Scientists who maintain the temperature record, which begins in 1880, calculate a global temperature anomaly each year to determine how much temperatures have changed compared to temperatures from 1951–1980.

    Every month from June through December 2023 came in as the hottest month on record. July ranked as the hottest month ever recorded.

    But what caused 2023, especially the second half of it, to be so hot? Scientists asked themselves this same question. Here is a breakdown of primary factors that scientists considered to explain the record-breaking heat.

    The long-term rise in greenhouse gases is the primary driver.

    For more than 100 years, humans have been burning fossil fuels such as coal, gas, and oil to power everything from lightbulbs and cars to factories and cities. These actions, along with changes in land use, have led to a rise in greenhouse gases in the atmosphere. Greenhouse gases act like a blanket trapping heat around the planet. The more of them you add, the thicker that blanket becomes, further heating Earth.

    https://eoimages.gsfc.nasa.gov/image...60x3240p30.mp4

    In May 2023, carbon dioxide concentrations in the atmosphere peaked at 424 parts per million at NOAA’s Mauna Loa Observatory, Hawaii. The annual peak has been steadily rising since measurements began in 1958. (Other global carbon measurement projects showed similarly high numbers.) Extending the record back even further with ice cores, carbon dioxide concentrations are the highest they have been in at least 800,000 years.

    “We’re going to continue to have records be broken because the baseline temperature is moving up all the time,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies in New York City. “The cause of that warming trend over the last 50 to 60 years is dominated by our changes to greenhouse gases, particularly carbon dioxide and methane.”

    NASA
    __________




    The Greenland ice cap is losing an average of 30m tonnes of ice an hour due to the climate crisis, a study has revealed, which is 20% more than was previously thought.

    Some scientists are concerned that this additional source of freshwater pouring into the north Atlantic might mean a collapse of the ocean currents called the Atlantic meridional overturning circulation (Amoc) is closer to being triggered, with severe consequences for humanity.

    Major ice loss from Greenland as a result of global heating has been recorded for decades. The techniques employed to date, such as measuring the height of the ice sheet or its weight via gravity data, are good at determining the losses that end up in the ocean and drive up sea level.

    However, they cannot account for the retreat of glaciers that already lie mostly below sea level in the narrow fjords around the island. In the study, satellite photos were analysed by scientists to determine the end position of Greenland’s many glaciers every month from 1985 to 2022. This showed large and widespread shortening and in total amounted to a trillion tonnes of lost ice.

    “The changes around Greenland are tremendous and they’re happening everywhere – almost every glacier has retreated over the past few decades,” said Dr Chad Greene, at Nasa’s Jet Propulsion Laboratory in the US, who led the research. “It makes sense that if you dump freshwater on to the north Atlantic Ocean, then you certainly get a weakening of the Amoc, though I don’t have an intuition for how much weakening.”

    The Amoc was already known to be at its weakest in 1,600 years and in 2021 researchers spotted warning signs of a tipping point. A recent study suggested the collapse could happen as soon as 2025 in the worst-case scenario. A significant part of the Greenland ice sheet itself is also thought by scientists to be close to a tipping point of irreversible melting, with ice equivalent to 1-2 metres of sea level rise probably already expected.

    The study, published in the journal Nature, used artificial intelligence techniques to map more than 235,000 glacier end positions over the 38-year period, at a resolution of 120 metres. This showed the Greenland ice sheet had lost an area of about 5,000 sq km of ice at its margins since 1985, equivalent to a trillion tonnes of ice.

    The most recent update from a project that collates all the other measurements of Greenland’s ice found that 221bn tonnes of ice had been lost every year since 2003. The new study adds another 43bn tonnes a year, making the total loss about 30m tonnes an hour on average.

    The scientists said: “There is some concern that any small source of freshwater may serve as a ‘tipping point’ that could trigger a full-scale collapse of the Amoc, disrupting global weather patterns, ecosystems and global food security. Yet freshwater from the glacier retreat of Greenland is not included in oceanographic models at present.” The influx of less dense freshwater into the sea slows the usual process of heavier salty water sinking in the polar region and driving the Amoc.

    Prof Tim Lenton, at the University of Exeter, UK, and not part of the study, said: “This additional freshwater input to the north Atlantic is a concern, particularly for the formation of deep water in the Labrador and Irminger Seas within the subpolar gyre, as other evidence suggests these are the regions most prone to being tipped into an ‘off’, or collapsed state.”

    “That would be like a partial Amoc collapse, but unfolding faster and having profound impacts on the UK, western Europe, parts of North America, and the Sahel region, where the west African monsoon could be severely disrupted,” he said. “Whether this previously unaccounted source is enough freshwater to make a difference depends on how close we are to that subpolar gyre tipping point. Recent models suggest it could be close already at the present level of global warming.”

    However, Prof Andrew Shepherd, at the University of Northumbria, UK, said: “Although there was a step-change in glacier retreat at the turn of the century, it’s reassuring to see that the pace of ice loss has been steady since then and is still well below the levels needed to disturb the Amoc.”

    The discovery of the extra ice loss is also important for calculating the Earth’s energy imbalance, ie how much extra solar heat the Earth is trapping due to human-caused greenhouse gas emissions, said Greene. “It takes a lot of energy to melt 1tn tonnes of ice. So if we want very precise energy balanced models for the Earth, this has to be accounted for.”

    The glaciers analysed in the study were mostly below sea level already, so the lost ice was replaced by sea water and did not affect sea level directly. But Green said: “It almost certainly has an indirect effect, by allowing glaciers to speed up. These narrow fjords are the bottleneck, so if you start carving away at the edges of the ice, it’s like removing the plug in the drain.”

    Chad and colleagues also analysed the extent of Antarctic ice shelves over time in a study published in 2022. It found that the total lost from the ice shelves since 1997 was doubled to about 12tn tonnes when the shrinking areal extent of the shelves was accounted for and added to the thinning of the shelves.

    __________



    A new World Economic Forum report, published today, warns that by 2050 climate change may cause an additional 14.5 million deaths and $12.5 trillion in economic losses worldwide. Despite the stark findings, there is still time for global stakeholders to take decisive, strategic action to counter these forecasts and mitigate the health impacts of climate change globally.

    The report, Quantifying the Impact of Climate Change on Human Health, developed in collaboration with Oliver Wyman, analyses the climate crisis through a new lens by providing a detailed picture of the indirect impact climate change will have on human health, the global economy and healthcare systems around the world, and offering actionable strategies to mitigate and prepare for this looming threat.

    “While there has been much discussion about the impact of climate change on nature and the global economy, some of the most pressing consequences of the Earth’s rising temperatures will be on human health and the global healthcare system,” said Shyam Bishen, Head of the Centre for Health and Healthcare and Member of the Executive Committee at the World Economic Forum. “Recent progress will be lost unless critical emission reduction and mitigation measures are improved, and decisive global action is taken to build climate resilient and adaptable health systems.”

    The report quantifies the health consequences of climate change, both in terms of the health outcomes (mortality and healthy lives lost) and the economic costs to the healthcare system, estimated to be a further $1.1 trillion in extra costs by 2050. The analysis is based on scenarios developed by the Intergovernmental Panel on Climate Change (IPCC) on the most likely trajectory for the planet’s rising average temperature, 2.5° to 2.9° Celsius over pre-industrial levels.

    Climate-driven health effects

    The report analyses six major climate-driven event categories as key multi-pronged drivers of negative health impacts: floods, droughts, heat waves, tropical storms, wildfires and rising sea levels.

    Floods were found to pose the highest acute risk of climate-induced mortality, accounting for 8.5 million deaths by 2050. Droughts, indirectly linked to extreme heat, are the second-highest cause of mortality, with an anticipated 3.2 million deaths. Heat waves take the highest economic toll at an estimated $7.1 trillion by 2050 due to the loss in productivity. Excess deaths attributed to air pollution, caused by fine particulate and ozone pollution are expected to be the largest contributor to premature death with almost 9 million deaths a year.

    Climate change will also trigger a catastrophic rise across several climate-sensitive disease outcomes, including vector-borne disease, which will likely impact previously less affected regions such as Europe and the United States. By 2050, an additional 500 million people may be at risk of exposure to vector-borne diseases, the report finds.

    “The climate crisis is a health crisis, and it is driving a vicious cycle of disease, economic devastation and suffering. It is clear from this report that we are still to understand the full impact,” said Vanessa Kerry, CEO of Seed Global Health and WHO Special Envoy for Climate Change and Health. “If we fail to act, not only will the death toll be staggering but we also risk losing progress made over decades to improve health outcomes around the world. Countries least able to afford these shocks – and who contribute the least to global emissions – will be impacted the most.”

    Increased inequality

    The report warns that climate change will further entrench global health inequities, with the most vulnerable populations, including women, youth, elderly, lower-income groups and hard-to-reach communities, the most affected.

    Regions such as Africa and southern Asia face heightened vulnerability to climate change impacts exacerbated by existing resource limitations, adequate infrastructure and essential medical equipment, further complicating their ability to address and adapt to environmental challenges.

    Need for collaboration

    Despite these stark findings, the new research shows that there is still time for global stakeholders to take decisive, strategic action to counter these forecasts and mitigate the health consequences of climate change. Intensified multistakeholder collaboration, across borders and industries, as well as a comprehensive transformation of the global health system to make it more resilient, adaptable and equitable will be crucial steps to achieve this.

    "Our analysis sheds light on the profound impact of climate change on mortality, morbidity and the interconnected macroeconomic landscape, with healthcare systems alone likely having to bear an additional cost of $1.1 trillion due to climate change,” said Sam Glick, Global Leader of Health and Life Sciences at Oliver Wyman. “It is clear that we need sustained action if we are to mitigate the far-reaching consequences of climate change and ensure a healthy future for all.”

    About the Centre for Health and Healthcare Climate and Health Initiative

    The World Economic Forum is convening climate and health stakeholders across sectors and industries to form expert working groups to focus on infrastructure and services; treatments, diagnostics and devices; and health workforce and community. These groups will address interventions with a focus on health outcomes covering infectious and vector-borne diseases, non-communicable illnesses, food and water security and mental health.

    __________

    • 2024 predictions


    Zeke Hausfather - With 2023 in the books as the hottest year on record by a sizable margin, what is likely to happen in 2024?

    Four different groups have all provided estimates, which have it similar to (and likely slightly warmer than) 2023, albeit with large uncertainties: https://twitter.com/hausfath/status/1748443521043104033




  9. #6784
    Guest Member S Landreth's Avatar
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    Last year was the warmest since records began in the mid-1800s – and likely for many thousands of years before.

    It was the first year in which average global temperatures at the surface exceeded 1.5C above pre-industrial levels in at least one global temperature dataset.

    Here, Carbon Brief examines the latest data across the oceans, atmosphere, cryosphere and surface temperature of the planet.

    Noteworthy findings from this 2023 review include…


    • Global surface temperatures: It was the warmest year on record by a large margin – at between 1.34C and 1.54C above pre-industrial levels across different temperature datasets.
    • Exceptional monthly temperatures: Global temperatures set a new record each month between June and December. September smashed the prior record for the month by a “gobsmacking” 0.5C.
    • Warmest over land: It was the first year the global average land temperature was more than 2C above pre-industrial levels.
    • Warmest over oceans: It was the first year that global average ocean surface temperatures exceeded 1C compared with pre-industrial levels.
    • Ocean heat content: It was the warmest year on record for ocean heat content, which increased notably between 2022 and 2023.
    • Regional warming: It was the warmest year on record in 77 countries – including China, Brazil, Austria, Bangladesh, Germany, Greece, Ireland, Japan, Mexico, the Netherlands, South Korea and Ukraine – and in areas where 2.3 billion people live.
    • Unusual warmth: 2023 was much warmer than scientists estimated it would be at the start of the year and there remain open questions about what precise factors have driven the exceptional warmth. Even El Niño – the usual suspect behind record warm years – does not clearly explain 2023 temperatures.
    • Comparison with climate models: Observations for 2023 are above the central estimate of climate model projections in the Intergovernmental Panel on Climate Change (IPCC) sixth assessment report, but well within the model range.
    • Warming of the atmosphere: It was the warmest year in the lower troposphere – the lowest part of the atmosphere. The stratosphere – in the upper atmosphere – is cooling, due in part to heat trapped in the lower atmosphere by greenhouse gases.
    • Sea level rise: Sea levels reached new record-highs, with notable acceleration over the past three decades.
    • Shrinking glaciers and ice sheets: Cumulative ice loss from the world’s glaciers and from the Greenland ice sheet reached a new record high in 2023, contributing to sea level rise.
    • Greenhouse gases: Concentrations reached record levels for CO2, methane and nitrous oxide.
    • Sea ice extent: Arctic sea ice saw its sixth-lowest minimum extent on record, while Antarctic sea ice saw a new record low extent for almost the entire year, much of it by an exceptionally large margin.
    • Looking ahead to 2024: Carbon Brief predicts that global average surface temperatures in 2024 are most likely to be slightly warmer than 2023 and set a new all-time record. However, large uncertainties remain given how exceptionally and unexpectedly warm 2023 was.


    Temperature record

    NOAA GlobalTemp - 1.34C
    NASA GISTEMP - 1.39C*
    Hadley/UAE HadCRUT5 - 1.46C
    Copernicus/ECMWF - 1.48C
    Berkeley Earth - 1.54C



    _________



    Climate change has caused ocean temperatures to steadily rise, which, experts warned senators Wednesday, could significantly harm the fishing industry.

    Andrea Dutton, a professor at the University of Wisconsin–Madison, said burning fossil fuels primarily drives climate change, which could cause widespread economic and environmental problems.

    Fossil fuels generate high levels of carbon dioxide, which, in oceans, could cause heat waves and create acidic seawater that could harm anything living in the ecosystem.

    Rashid Sumaila, a University Killam professor and research chair at the University of British Columbia’s Institute for the Oceans and Fisheries, said fisheries catch about 120 million tons of fish annually, generating about $240 billion in worldwide revenue.

    “Now in the U.S., and the chair has given us some numbers that are quite similar, in 2020 commercial and recreational saltwater fishing alone generated over $250 billion in sales,” Sumaila said. “So lots of dollars, and the contribution to America’s [gross domestic product] is estimated to be over $110 billion a year, which supports 1.7 million American jobs in the marine sector. Huge, huge benefits to everybody.”

    If climate change kills or forces fish to move, crucial food sources and jobs will be gone, Sumaila said.

    Kyle Schaefer works as a fishing guide in Maine and is the founder and owner of a fishing lodge in the Bahamas.

    Warming waters and severe weather events like hurricanes and heavy rains have significantly affected his business, Schaefer told the Senate Committee on the Budget on Wednesday.

    “My businesses succeed only because of thriving healthy ecosystems and relatively predictable climate patterns,” Schaefer said. “Unfortunately, in large part due to climate change, our oceans are now desperately lacking the stability, balance and the abundance that we rely on.”

    Schaefer said many fish are moving to different areas, which strains ecosystems as local fish must now compete with new species for limited resources.

    There have been five consecutive years of failed spawning events for striped bass in the Chesapeake Bay, which is a problem, Schaefer explained, because the fish are estimated to have a $7.7 billion impact on the region’s gross domestic product (GDP), according to a study from Southwick Associates.

    Schaefer also told lawmakers that these fish are a primary example of the effects of climate change, and these conditions may force him to close his business if they do not improve.

    “I can’t hide from it,” Schaefer said. “I dream of passing healthy businesses down to my almost 3-year-old son one day. I want to be proud of what will lead to future generations.”

    Sen. Ron Johnson (R-Wis.) spoke for ranking member Chuck Grassley (R-Iowa), who is recovering after being hospitalized for an infection. The senator, who is the chamber’s oldest member, is recovered enough to vote but not yet to serve as a ranking member, Johnson said.

    While Johnson is not a climate change denier, he said he disagrees with the extent of the actions taken to prevent it.

    “Instead of discussing the most pressing fiscal or maritime issues, Democrats have elected to hold an ocean warming hearing to scare people about climate change,” Johnson said.

    Chair Sheldon Whitehouse (D-R.I.) explained the importance of making changes now to reduce climate change to protect against greater economic impacts in the future, citing research from Deloitte.

    “Deloitte has projected that if we do nothing about climate change, the cost [to] global GDP would be $178 trillion negative, that if we hit net-zero by 2050, that will create $43 trillion in added GDP globally for a $220 trillion swing between getting this right and getting this wrong,” Whitehouse said.

    Dutton said that most current data estimating climate change impact is underestimated and that it is essential to make changes before critical thresholds are reached.

    “The most important part of my message today is that because humans are driving rapid warming of our planet — this is good news — it means we are also the solution to the problem,” Dutton said. “Our climate future is not written in stone.”

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    2023 is the tenth year in succession that has equalled or exceeded 1.0 °C above the pre-industrial period (1850-1900).

    The global average temperature for 2023 was 1.46 °C above the pre-industrial baseline; 0.17 °C warmer than the value for 2016, the previous warmest year on record in the HadCRUT5 global temperature dataset which runs from 1850.

    “Year-to-year variations sit on a background of around 1.25 °C warming in global average temperatures above pre-industrial levels. This warming is attributable to human-induced climate change through greenhouse gas emissions.”




    _______




    Prof Richard Betts - Our forecast of the atmospheric CO2 rise for 2024 is out

    To limit global warming to 1.5°C, the build-up of CO2 in the air would need to stop very soon

    But with a rise of 2.84 ± 0.54 ppm expected this year, there's no sign that the CO2 rise is slowing




    ________




    Documents show industry-backed Air Pollution Foundation uncovered the severe harm climate change would wreak

    The fossil fuel industry funded some of the world’s most foundational climate science as early as 1954, newly unearthed documents have shown, including the early research of Charles Keeling, famous for the so-called “Keeling curve” that has charted the upward march of the Earth’s carbon dioxide levels.

    A coalition of oil and car manufacturing interests provided $13,814 (about $158,000 in today’s money) in December 1954 to fund Keeling’s earliest work in measuring CO2 levels across the western US, the documents reveal.

    Keeling would go on to establish the continuous measurement of global CO2 at the Mauna Loa Observatory in Hawaii. This “Keeling curve” has tracked the steady increase of the atmospheric carbon that drives the climate crisis and has been hailed as one of the most important scientific works of modern times.

    The fossil fuel interests backed a group, known as the Air Pollution Foundation, that issued funding to Keeling to measure CO2 alongside a related effort to research the smog that regularly blighted Los Angeles at the time. This is earlier than any previously known climate research funded by oil companies.

    In the research proposal for the money – uncovered by Rebecca John, a researcher at the Climate Investigations Center, and published by the climate website DeSmog – Keeling’s research director, Samuel Epstein, wrote about a new carbon isotope analysis that could identify “changes in the atmosphere” caused by the burning of coal and petroleum.

    “The possible consequences of a changing concentration of the CO2 in the atmosphere with reference to climate, rates of photosynthesis, and rates of equilibration with carbonate of the oceans may ultimately prove of considerable significance to civilization,” Epstein, a researcher at the California Institute of Technology (or Caltech), wrote to the group in November 1954.

    Experts say the documents show the fossil fuel industry had intimate involvement in the inception of modern climate science, along with its warnings of the severe harm climate change will wreak, only to then publicly deny this science for decades and fund ongoing efforts to delay action on the climate crisis.

    “They contain smoking gun proof that by at least 1954, the fossil fuel industry was on notice about the potential for its products to disrupt Earth’s climate on a scale significant to human civilization,” said Geoffrey Supran, an expert in historic climate disinformation at the University of Miami.

    “These findings are a startling confirmation that big oil has had its finger on the pulse of academic climate science for 70 years – for twice my lifetime – and a reminder that it continues to do so to this day. They make a mockery of the oil industry’s denial of basic climate science decades later.”

    The newly discovered documents now show the industry knew of CO2’s potential climate impact as early as 1954 via, strikingly, the work of Keeling, then a 26-year-old Caltech researcher conducting formative work measuring CO2 levels across California and the waters of the Pacific ocean. There is no suggestion that oil and gas funding distorted his research in any way.

    The findings of this work would lead the US scientist to further experiments upon the Mauna Loa volcano in Hawaii that were to provide a continual status report of the world’s dangerously-rising carbon dioxide composition.

    _________



    While 2023 made headlines for smashing global temperature records, last year also saw some truly remarkable events in the Antarctic.

    After crashing to a record-low summer extent in February, sea ice around the southern continent regrew extremely slowly.

    By July, when sea ice should be approaching its maximum winter coverage, there was an area of ice “missing” that was bigger than Algeria – the world’s 10th largest country.

    When the annual maximum extent arrived – early – it was the smallest on record by a “wide margin”.

    This made 2023 the second record-breaking year in a row, continuing the recent erratic swings in sea ice cover that had otherwise been preceded by several decades of steady, gradual increase.

    In our new paper, published in the Royal Meteorological Society’s journal Weather, my coauthor and I explore what happened to sea ice in 2023, what caused the dramatic events and what the implications are for the future.

    The importance of Antarctic sea ice

    Antarctic sea ice is a critical puzzle piece in the regional and global climate picture.

    The frozen continent as a whole acts as the Earth’s principal refrigerator, reflecting the sun’s energy from its bright, white mirror-like surface, helping keep temperatures cool.

    Sea ice formation around its coastline acts as an engine for ocean currents and influences weather patterns that can have far-reaching effects.

    Floating ice also acts as a buffer that can protect the exposed edges of the ice sheet from the destructive action of waves, meaning that it can curb Antarctica’s contribution to sea level rise. ​​By influencing the availability of water from the open ocean, it also affects how much snow can fall to replenish the ice sheet’s losses.

    And sea ice is vitally important for marine life, as demonstrated by the “catastrophic breeding failure” of Emperor penguin chicks following the (then) record-low sea ice coverage in 2022.

    Long-term trends

    Thanks to satellite data, scientists have a detailed picture of how Arctic and Antarctic sea ice have behaved since the late 1970s. And for Antarctica, this picture has been something of a puzzle.

    Between 1979 and 2015, average Antarctic sea ice extent – the area of ocean with at least 15% sea ice cover – increased slightly, but fairly steadily. This is in stark contrast to the Arctic, where sea ice at the minimum summer extent plummeted by nearly 12% per decade.

    Then, after a record high year in 2014, Antarctic sea ice extent dropped to a record low in 2017. Several years of low sea ice came after that, with the summer minimum record smashed in 2022, when it fell below 2m square kilometres for the first time.

    How extreme was 2023?

    Antarctic sea ice waxes and wanes throughout the year, reaching a minimum in February at the end of the southern-hemisphere summer and a maximum in September after a long, cold winter.

    This seasonal expansion causes the area covered by sea ice to grow six-fold within a single year – as the chart below shows. It depicts Antarctic sea ice extent for each day of 2023 (blue line), along with how it compares to the historical range (blue shading) and the record low for the time of year (dotted line).




    As the chart shows, 2023 was an exceptional year in the satellite record, remaining well below average for the entire year.

    The year started with a record-breaking minimum extent of 1.79m km2 in February 2023, which was 10% lower than the already record-breaking 2022.

    Although the autumn freeze-up started off as usual, from April the seasonal expansion of sea ice was very slow. By July, the total sea ice extent was 13.5m km2 – 15% lower than average for the month.

    The area of “missing” sea ice for the month of July, relative to the 1981–2010 average, was nearly two-and-a-half million square kilometres – an area larger than Algeria.

    The period of extreme departure from average persisted from mid-May until mid-November, with conditions recovering a little, meaning that by the end of the year, they were no longer record-breaking.

    Overall, the largest deviations from average conditions in 2023 were recorded in winter (June to August). To see this in context, the chart below shows winter sea ice extent from 1979 to 2023 and highlights how dramatically low winter sea ice was last year.


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    The high-profile climate scientist Michael Mann has been awarded $1m by a jury in a defamation lawsuit against two conservative writers who compared his depictions of global heating to the work of a convicted child molester.

    The case stretches back 12 years.

    Regardless, in 2012, the Competitive Enterprise Institute, a libertarian thinktank, published a blogpost by Rand Simberg that compared investigations by Penn State University into Mann’s work with the case of Jerry Sandusky, a former assistant football coach who was convicted of sexually assaulting multiple children.

    “Mann could be said to be the Jerry Sandusky of climate science, except for instead of molesting children, he has molested and tortured data,” Simberg wrote. Another writer, Mark Steyn, later referenced Simberg’s article in his own piece in National Review, calling Mann’s research “fraudulent”.

    Mann sued both men and their publishers. In 2021 a judge dismissed the two outlets as defendants, saying they could not be held liable, but the claims against the individuals remained.

    Prof Michael E. Mann - Our statement: https://twitter.com/MichaelEMann/sta...16002518622522





    Michael Mann Wins Defamation Case
    Last edited by S Landreth; 11-02-2024 at 05:12 AM.

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    Copernicus – January 2024 was the warmest January recorded and January’s global sea surface (60°S – 60°N) temperature was also the warmest recorded.







    Copernicus

    ____________




    Record temperatures in the Atlantic Ocean and the Gulf of Mexico in 2023 led to widespread coral bleaching and resulted in mass death for coral reefs across Florida, National Oceanic and Atmospheric Administration researchers said Wednesday.

    The scorching highs that lasted from June to October prompted marine scientists at NOAA to step up their reef monitoring across coastal areas, they said at an hourlong public education session Wednesday.

    The agency went from checking reefs yearly to monthly whenever possible, according to Nicole Besemer, an oceanographer with the federal organization. She helped present the agency's findings on coral in the Flower Garden Banks National Marine Sanctuary — the only one of its kind in the Gulf of Mexico — and in the Florida Keys.

    “Our environment is becoming unsuitable for some coral — we need to monitor and find out which elements of climate affect which corals, which corals they are and what they do for our environment,” Besemer said, describing why monitoring is vital in an age of climate change.

    Coral reefs represent one of the most important ecosystems in the world and are threatened by climate change.

    “Coral are animals,” Besemer said. “Coral move and feed and reproduce just like animals.”

    __________




    Collapse in system of currents that helps regulate global climate would be at such speed that adaptation would be impossible

    The circulation of the Atlantic Ocean is heading towards a tipping point that is “bad news for the climate system and humanity”, a study has found.

    The scientists behind the research said they were shocked at the forecast speed of collapse once the point is reached, although they said it was not yet possible to predict how soon that would happen.

    Using computer models and past data, the researchers developed an early warning indicator for the breakdown of the Atlantic meridional overturning circulation (Amoc), a vast system of ocean currents that is a key component in global climate regulation.

    They found Amoc is already on track towards an abrupt shift, which has not happened for more than 10,000 years and would have dire implications for large parts of the world.

    Amoc, which encompasses part of the Gulf Stream and other powerful currents, is a marine conveyer belt that carries heat, carbon and nutrients from the tropics towards the Arctic Circle, where it cools and sinks into the deep ocean. This churning helps to distribute energy around the Earth and modulates the impact of human-caused global heating.




    But the system is being eroded by the faster-than-expected melt-off of Greenland’s glaciers and Arctic ice sheets, which pours freshwater into the sea and obstructs the sinking of saltier, warmer water from the south.

    Amoc has declined 15% since 1950 and is in its weakest state in more than a millennium, according to previous research that prompted speculation about an approaching collapse.

    Until now there has been no consensus about how severe this will be. One study last year, based on changes in sea surface temperatures, suggested the tipping point could happen between 2025 and 2095. However, the UK Met Office said large, rapid changes in Amoc were “very unlikely” in the 21st century.

    The new paper, published in Science Advances, has broken new ground by looking for warning signs in the salinity levels at the southern extent of the Atlantic Ocean between Cape Town and Buenos Aires. Simulating changes over a period of 2,000 years on computer models of the global climate, it found a slow decline can lead to a sudden collapse over less than 100 years, with calamitous consequences.

    The paper said the results provided a “clear answer” about whether such an abrupt shift was possible: “This is bad news for the climate system and humanity as up till now one could think that Amoc tipping was only a theoretical concept and tipping would disappear as soon as the full climate system, with all its additional feedbacks, was considered.”

    Physics-based early warning signal shows that AMOC is on tipping course

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    NOAA – January 2024 was the warmest January recorded.




    NOAA

    __________


    • Prof Richard Betts - Climate change and deforestation risk an Amazon tipping point


    On current trends, we estimate that by 2050, 10 - 47% of Amazonian forests will exposed to compounding disturbances risking critical transitions: https://twitter.com/richardabetts/st...28615813689811

    Critical transitions in the Amazon forest system | Nature

    ___________




    Up to half of the Amazon rainforest could hit a tipping point by 2050 as a result of water stress, land clearance and climate disruption, a study has shown.

    The paper, which is the most comprehensive to date in its analysis of the compounding impacts of local human activity and the global climate crisis, warned that the forest had already passed a safe boundary and urged remedial action to restore degraded areas and improve the resilience of the ecosystem.

    Bernardo Flores of the Federal University of Santa Catarina, Brazil, the lead author of the study, said he was surprised by the results, which projected a potential shift from slow to rapid forest decline earlier than he had expected.

    The forest was already becoming weaker and more homogenous, he said. “By 2050, it will accelerate rapidly. We need to respond now. Once we pass the tipping point, we will lose control of how the system will behave.”

    This requires international action because even a local halt to deforestation would not prevent collapse without a global reduction in the CO2 emissions that are disrupting the climate.

    For 65 million years, Amazonian forests have withstood climatic variability, but the region is now exposed to unprecedented stress from drought, heat, fire and land clearance, which are penetrating even the deep central areas of the biome. This is altering the functioning of the forest, which in many areas is producing less rain than before, and turning a carbon sink into a carbon emitter.

    Concerns about an Amazon tipping point have been discussed for the past two decades, with previous models suggesting this could come when 20% to 25% of the forest is cleared. The new study, published in Nature on Wednesday, went further in its complexity, analysing evidence for five drivers of water stress and identifying critical thresholds that, if crossed, could trigger local, regional or even biome-wide forest collapse.

    It estimated that by 2050, 10% to 47% of Amazonian forests would be exposed to compounding disturbances that might trigger unexpected ecosystem-wide transitions and have an adverse knock-on effect for regional climate change.

    To prevent this, the study found that a safe boundary, which included a buffer zone, would be needed to keep deforestation to 10% of the Amazon region, and to keep global heating within 1.5C above pre-industrial levels.

    But overshoot has already happened. The study found 15% of the Amazon had already been cleared and another 17% had been degraded by human activity, such as logging, fires and under-canopy extraction. A further 38% of the Amazon may be weakened as a result of the prolonged droughts over the past decade.

    Using recent data collected on the ground, proxy indicators of ancient trends, and computer modelling that incorporates regional and global climate trends, the study traced three plausible ecosystem trajectories: a white-sand savanna, a degraded open canopy and a degraded forest – all of which would bring more fire and drought.

    Dry season temperatures are already 2C higher than they were 40 years ago in central and southern parts of the Amazon. By 2050, the models projected between 10 and 30 more dry days than now, and an increase in annual maximum temperatures of between 2C and 4C. The paper said this would expose “the forest and local peoples to potentially unbearable heat” and potentially reduce forest productivity and carbon storage capacity.

    Rainfall patterns are shifting. Since the early 1980s, swathes of the central and peripheral Amazon forest have become drier. Annual rainfall in the southern Bolivian Amazon has declined by up to 20mm. By contrast, western and eastern Amazon regions are becoming wetter. If these trends continued, the paper said, ecosystem resilience would be reshaped. Some regions would become savanna, whereas most of the rest of the Amazon was likely to persist in a degraded state.

    This will have a profound impact on local and regional populations. The Amazon is home to more than 10% of the Earth’s terrestrial biodiversity, stores 15-20 years’ worth of global CO2 emissions, contributes up to 50% of rainfall in the region and is crucial for moisture supply across South America. Its evapotranspiration helps to cool and stabilise the world’s climate. But its importance and complexity are not fully understood.

    ___________



    A new initiative merges satellite tracking with AI and other powerful computing to create an Eye of Sauron-style tool for tracking methane.

    Why it matters: Methane is a powerful planet-warming gas, and oil and gas infrastructure is among the largest sources.

    What's new: The Environmental Defense Fund next month will launch MethaneSAT, which will orbit Earth 15 times per day from 350 miles above.


    • Google is providing Cloud computing and applying AI to the satellite imagery.
    • The combined mapping and analyses create "unprecedented" power to pinpoint emissions — and give useful info to companies, researchers and the public, they said.
    • MIT Technology Review has more.


    The big picture: "We're effectively putting on a really high-quality set of glasses, allowing us to look at the Earth and these emissions with a sharpness that we've never had before," EDF chief scientist Steven Hamburg told reporters.

    What we're watching: How it might aid corporate and regulatory efforts.


    • And over 155 nations back a voluntary pledge to cut methane emissions by 30% by 2030 (relative to 2020).


    The bottom line: "This data puts a key into the hands of stakeholders around the world and gives them the ability to unlock reductions," Hamburg said.

    ___________



    Blistering heat waves and more frequent wildfires are reversing a generation of U.S. clean air gains, a new study has found.

    The peer-reviewed research by the climate analytics firm First Street Foundation projected that by midcentury, the increased levels of microscopic soot particles and ozone molecules entering Americans’ lungs will be back to the levels they were at in 2004 — before a decades-long federal campaign to clean up the air.

    Climate change is driving the U.S. from a pattern where the average poor air days are “unhealthy for some to ones which are unhealthy to all,” coauthor Jeremy Porter told The Hill.

    Porter said federal regulations drove consistent improvements in air quality from 1963 until about 2016 — when the negative impacts of climate change surpassed the positive pressure from clear air enforcement.

    “We’re seeing the biggest uptick in the most hazardous [air] days,” Porter said, though he noted every category of unhealthy air “was sliding up” in frequency.

    “We’re wiping out two decades in air quality gains,” he added.

    Those changes have already had subtle but far-reaching effects, according to the study.

    For example, falling air quality has driven up the number of days when children in Western states can’t safely play outside nearly fivefold since 2000.

    And about 14 million American households (about 10 percent) can expect to experience at least a week of Environmental Protection Agency (EPA)-designated “unhealthy” air quality each year.

    In some hot spots, those numbers are even worse: About 6 million of those households — located in hot spots across the West Coast, Midwest and Northeast — can expect two weeks a year of bad air.

    While these declines in air quality will happen across the country, they will be particularly pronounced on the West Coast, where ozone rising from baking asphalt combines with toxic particulates from wildfires and the burning of fossil fuels, First Street researchers found.

    Over the next 30 years — the length of the average mortgage — this region will see a noticeable uptick in bad air days, according to the study. Los Angeles, for example, currently experiences 47 days annually when the air is — at a minimum — unsafe for children and those with chronic illness; by 2054, First Street data projects Angelenos will face an additional week each year when it’s unhealthy for those groups to be outside.

    In California, “sensitive” groups make up most of the population: About 28 million people are elderly, young or have heart disease or diabetes — making up more than 70 percent of the population.

    And California isn’t alone. First Street researchers found that by 2054, most American cities — led by New York, Chicago, Los Angeles, Houston, Philadelphia and Jacksonville — will see dramatic growth in the number of households in areas with at least a week and a half of bad air per year.

    These changes are already showing up, driven by two very different contaminants, each with ties to climate change: PM2.5 and ozone.

    https://firststreet.org/press/first-...-atrocious-air

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    NASA – January 2024 was the warmest January recorded.




    NASA

    __________




    Atmospheric rivers are low-level jets of air that flow out of the tropics to the mid-latitudes. They are associated with extratropical cyclone systems. For more details, read this.

    Sometimes atmospheric rivers originate in the tropics, near Hawaii, and those are also called the Pineapple Express. Their origin in the tropics also explains why they carry enormous amounts of water vapor.




    When these atmospheric rivers hit California, they can cause enormous rainfall. The mechanism is straightforward: As an atmospheric river encounters the land, particularly the Sierra Nevada mountain range, the moist air is forced upwards — a process known as orographic lift. As the air rises, it cools and condenses, and rain falls out.

    Because the ocean never runs out of water, this weather pattern can bring neverending rain to the State. One storm in the 1860s brought continuous rain for nearly 43 days, leading to catastrophic flooding across much of California, particularly in the Central Valley, which transformed into an inland sea, reportedly up to 30 miles wide and 300 miles long. If such an event occurred today, the damage could top $1 trillion.

    What about climate change, you ask? A warmer planet has more water vapor in the atmosphere. And, everything else being the same, an atmospheric river carrying more water vapor will cause more rainfall when it hits land and starts rising.

    Because of the simplicity of this physical argument, the IPCC concluded that global warming will increase the precipitation from these events:

    Precipitation associated with extratropical storms and atmospheric rivers will increase in the future in most regions (high confidence).1

    Thus, we can conclude with confidence that climate change is making the event occurring in California right now worse than it would be without climate change.

    But by how much? If we assume a purely thermodynamic response (e.g., Clausius-Clayperon scaling), rain would increase by about 7% for every degree Celsius of warming of the atmosphere. But this neglects the dynamic response — e.g., impact of climate change on atmospheric circulations.

    My reading of the literature suggests that we don’t really have a good handle on this. Thus, a firm quantification of the impact of climate change on the rain in this event will await formal attribution analysis.

    In summary, atmospheric rivers are a high-consequence weather system, with significant implications for water resources and flood risk. The interaction between atmospheric rivers and climate change is complex, but the increase in moisture in the atmosphere will certainly lead to more intense rainfall. Changes in atmospheric circulation could ameliorate or enhance this, which future research should clarify.

    1 from executive summary of Chapter 8 of IPCC AR6 WG1

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