Around the world in 80 days cliff notes free#

Antarctic sea ice extent for April 2023 was 5.50 million square kilometers (2.12 million square miles).

This argues that the representation of clouds and their radiative impacts is important for accurately modeling heat input to the upper ocean as the Arctic transitions to being seasonally ice free. Looking to the future, their findings suggest that when the Arctic becomes seasonally ice free, the maximum sea surface temperature becomes three times more sensitive to clouds than in the pre-industrial era. However, as carbon dioxide levels rise and the sea ice retreats, the countering cooling effect of clouds grows. pre-industrial), sea ice covers the ocean through most of the summer, and clouds have little influence on sea surface temperatures.

Their study, based on climate model experiments, argues that with low levels of carbon dioxide (e.g. But as the ocean becomes ice-free, the high albedo of clouds can counteract the ocean warming expected from increased solar absorption. Over snow- and ice-covered areas, clouds normally have a similarly high reflectance, reflecting most of the sun’s energy back out to space. This is because as the Arctic warms and sea ice retreats earlier, more solar radiation is absorbed by the upper ocean, causing the ocean to warm. offers evidence that as carbon dioxide levels rise, summer clouds will have an increasingly strong influence on Arctic sea surface temperatures (SSTs). Clouds and Arctic sea iceĪ new study by Sledd et al. This is roughly equivalent to twice the size of Ukraine. Based on the linear trend, since 1979, April has lost 1.65 million square kilometers (637,000 square miles) of ice. The downward linear trend for Arctic sea ice extent in April over the 45-year satellite record is 37,000 square kilometers (14,300 square miles) per year, or 2.5 percent per decade relative to the 1981 to 2010 average (Figure 3). Monthly April ice extent for 1979 to 2023 shows a decline of 2.5 percent per decade. April 2023 compared to previous yearsįigure 3. Similarly, below-average temperatures over Alaska were driven by the combination of a strong low pressure area in the Gulf of Alaska and high pressure in the Beaufort Sea, driving air generally southward from the ice-covered Arctic Ocean. The clockwise winds around a separate high-pressure center over Scandinavia brought warm winds from the south over the Barents Sea, consistent with the above air average temperatures in that area. The sea level pressure pattern was characterized by fairly high pressure over most of the Arctic Ocean (Figure 2b).

Around the world in 80 days cliff notes free#

While temperatures were modestly above average over the Barents Sea, these areas are already largely free of sea ice. This helps to explain the slow rate of sea ice loss during April. Yellows and reds indicate high air pressure blues and purples indicate low pressure.Ĭredit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences LaboratoryĪir temperatures at the 925 hPa level in April were near average to below average over most of the Arctic Ocean (Figure 2a). This plot shows average sea level pressure in the Arctic in millibars for April 2023. The ice edge is also north of its usual position over part of the Bering Sea. At the end of the month, extent remained below average primarily in the Barents Sea. Overall, sea ice extent decreased 690,000 square kilometers (266,000 square miles) during April 2023, compared to the 1981 to 2010 average April decrease of 1.16 million square kilometers (448,000 square miles). Toward the end of the month, extent reached the lowest decile of daily extents as assessed over the satellite record. The rate of sea ice loss through April was only 20,600 square kilometers (8,000 square miles) per day, well below the 1981 to 2010 average of 36,400 square kilometers (14,000 square miles) per day. The average monthly extent was 700,000 square kilometers (270,000 square miles) below the 1981 to 2010 average of 14.69 million square kilometers (5.67 million square miles), but 560,000 square kilometers (216,000 square miles) above the record low set in April 2019 (Figure 1b). The April 2023 average Arctic sea ice extent was 13.99 million square kilometers (5.40 million square miles), tied with 2004 as the tenth lowest April in the satellite record (Figure 1a). Sea Ice Index data.Ĭredit: National Snow and Ice Data Center The gray areas around the median line show the interquartile and interdecile ranges of the data.

2023 is shown in blue, 2022 in green, 2021 in orange, 2020 in brown, 2019 in magenta, and 2012 in dashed brown. The graph above shows Arctic sea ice extent as of May 2, 2023, along with daily ice extent data for four previous years and the record low year.