JMA –
April 2017
The monthly anomaly of the global average surface temperature in April 2017 (i.e. the average of the near-surface air temperature over land and the SST) was +0.38°C above the 1981-2010 average (+0.77°C above the 20th century average), and was the 2nd warmest since 1891. On a longer time scale, global average surface temperatures have risen at a rate of about 0.76°C per century.
Five Warmest Years (Anomalies)
1st. 2016 (+0.54°C), 2nd. 2017 (+0.38°C), 3rd. 2014,1998 (+0.31°C), 5th. 2015 (+0.30°C)
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NASA - April 2017 (
second warmest recorded)
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NOAA – April 2017 (second warmest recorded)
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Copernicus – April 2017
April 2017 extended the spell of exceptional global warmth that has now lasted since mid-2015. Although the global temperature anomaly peaked in February 2016 and declined steadily until June that year, it rose again in July and August, and has remained high since. February and March 2017 were the most anomalous months since April 2016. April 2017 was less extreme, but still:
• 0.51 degrees C warmer than the average April from 1981-2010;
• the second warmest April on record;
• 0.18 degrees C cooler than April 2016.
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Glacier National Park Is
Losing Its Glaciers
Of the 150 glaciers that existed it the park in the late 19th century,
only 26 remain.
The loss of glaciers potentially affects not just tourism to the park, which hit a record 2.9 million visitors last year, but also local ecosystems that depend on the summer release of glacial meltwater.
The pristine, 1 million-acre park sits along the border with Canada in Montana and has long been a poster child for climate change in U.S. national parks. Side-by-side photo comparisons show in the starkest terms just how far some glaciers have retreated, with some only reduced to small nubs of ice.
The retreat has happened as temperatures in the region have risen by 1.5°F since 1895 as heat-trapping greenhouse gases have continued to accumulate in the atmosphere.
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Alaska’s
thawing soils are now
pouring carbon dioxide into the air
The
new study, published in the Proceedings of the National Academy of Sciences, suggests that frozen northern soils — often called permafrost — are unleashing an increasing amount of carbon dioxide into the air as they thaw in summer or subsequently fail to refreeze as they once did, particularly in late fall and early winter.
“Over a large area, we’re seeing a substantial increase in the amount of CO2 that’s coming out in the fall,” said Roisin Commane, a Harvard atmospheric scientist who is the lead author of the study. The research was published by 19 authors from a variety of institutions, including NASA’s Jet Propulsion Laboratory and the National Oceanic and Atmospheric Administration.
The study, based on aircraft measurements of carbon dioxide and methane and tower measurements from Barrow, Alaska, found that from 2012 through 2014, the state emitted the equivalent of 220 million tons of carbon dioxide gas into the atmosphere from biological sources (the figure excludes fossil fuel burning and wildfires). That’s an amount comparable to all the emissions from the U.S. commercial sector in a single year.
The chief reason for the greater CO2 release was that as Alaska has warmed up, emissions from once frozen tundra in winter are increasing — presumably because the ground is not refreezing as quickly.
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The warming that has occurred over the past 160 years has not been the same everywhere. Certain regions, such as the Arctic, have warmed far more than the Southern Ocean for example. How well do our climate models represent these differences?
One way of examining the regional differences in warming is to look at the average for each latitude (or zonal mean). Instead of showing monthly values of global average surface temperature (as in some previous graphics), this shows annual values, averaged around latitude circles. Thanks to Matt England (UNSW) for suggesting this zonal mean idea.
The
figure below shows the zonal mean from observations (left) and the average of many different climate models (right). The different coloured lines represent every year from 1861-2016. The dashed horizontal lines indicate the 1.5°C and 2°C global temperature targets suggested by the UNFCCC in the Paris Agreement.