Observed AA43 temperature trend in the Arctic
The AA43, or observed AA43 arctic warming temperature trend, is a measure of climate change. This temperature trend is strongest in the late autumn and weakest during the warm season. The AA43 temperature trend in the Arctic is modeled by CMIP6 climate models and ERA-Interim reanalysis data, and it shows that the region has warmed at a rate five times faster than the global average. In contrast, the warming ratio during the months of June-August is only around two. The increase in temperature is due to newly opened water areas, which enhance long-wave radiation and turbulent fluxes of sensible heat.
CMIP5 and GE models do not reproduce the observed AA43 temperature trend, because CMIP5 and ERA6 have a tendency to produce extreme AA43 values in the early 21st century. Both models show a gradual intensification of AA in the future, with maximum warming in the Eurasian sector of the Arctic Ocean near Svalbard and Novaya Zemlya.
The CMIP6 models reproduce observed AA43 only marginally better than the CMIP5 models. Some of the CMIP6 models show a five-fold warming trend in the Arctic, while others show a fourfold increase. In the end, climate models consistently underestimate the AA. For that reason, the CMIP6 models should be used cautiously. They tend to underestimate it and do not capture the full extent of the recent warming.
Although AA43 temperature trend in the Arctic is more stable than AA44, it remains a highly uncertain indicator of climate change. Several factors are implicated, including sea ice loss, the oceanic heat exchange, and the lapse-rate feedback. Sea ice feedback is important, but it is often not taken into account. If it is important, the reanalysis data should be used.
Although the ice sheet of Greenland is an important part of climate change, it has increased twice as fast as the global average. This is known as the Arctic amplification. Climate models and instrumental observations all indicate this. It is important to understand the full impacts of Arctic warming on the globe. It will help us develop climate mitigation and adaptation strategies to combat it. If the ice sheet melts, sea levels could rise.
Observed AA43 temperature trend and climate change projections from the Arctic Monitoring and Assessment Program show that the Arctic has been warming faster than the global average since 1979. Compared to the 1981-2010 period, a trend of three degrees Celsius over the last decade has been observed. As a result, the Arctic climate is becoming progressively more extreme. Even if it is less extreme than the rest of the world, there is still a growing risk of irreversible changes in the climate.
The CMIP5 climate model outputs show that AA43 is much faster than the global average. At the start of the 21st century, observed AA43 is more than four times higher than the global mean. This trend is also much faster than previously published research, which used 30 to 40-year time intervals and pegged it at two to three. The authors believe this to be a natural phenomenon.
This is an example of how the observed AA43 temperature trend has the potential to cause catastrophic climate change. This is why a better understanding of the effects of climate change in the Arctic is essential. There are numerous factors that contribute to climate change, including sea-level rise, the development of shipping routes, and risks associated with fossil fuel reserves. Furthermore, studies have shown that Arctic change and the changes in mid latitude weather patterns are closely linked, although the relationship is complicated and inconsistent.
The sea ice extent of the Arctic Ocean is a reliable indicator of climate change. The extent of multi-year ice in the Arctic Ocean has decreased substantially since 1979. In summer 2021, it reached its second lowest extent since 1985. Similarly, the post-winter sea ice volume in April 2021 was the lowest since records began in 2010.
Observed AA43 temperature trend in the Arctic and global mean warming trends
While the multi-data-set average of temperatures in the Arctic and the globe is 0.19 C decade-1, the observed AA43 is almost double this figure (3.8 C decade-1). This difference reflects a substantial warming in the Eurasian sector of the Arctic, near Svalbard and Novaya Zemlya. Large continental regions of North America, like the United States and Canada, may not show statistically significant trends in temperature.
The recent Arctic warming rate has increased more rapidly than the global warming rate. The accelerated loss of sea ice in the summer is also associated with substantial variations in surface air temperature. Global mean temperatures converge to the Arctic, albeit at a faster rate. This difference is attributed to a phenomenon known as Arctic Amplification. These changes include a reduction in summer albedo, an increase in total water vapor, and a decrease in cloudiness.
The AA43 discrepancy between the two datasets depends on the starting year. The AA43 of the Arctic is consistently negative from 1950 to 1980, but it can be five times larger in the north. This large spread reflects the fact that AA43 on the 43-year time scale is highly correlated with model uncertainties, even though CMIP6 realizations do not capture all of the effects of anthropogenic aerosols.
There are also differences between the observed AA43 temperature trend in the Arctic and global mean warming trends. Observed AA43 temperature trends show that the Arctic is warming faster than the world. This is referred to as “arctic amplification,” and can be observed in climate models, instrumental observations, and paleo-climate proxy records. While this is not always the case, the warming rate in the Arctic is twice as high as the global average.
The sea ice thickness in the Arctic has decreased at a rate of 12.8% decade-1. By September 23, 2018, the Arctic SIE was only 1.5 m thick, which was the sixth lowest ever. This is a sign of Arctic melt season. The sea ice in the Arctic is increasingly thin, and the SIE may continue to decline throughout the Arctic. The Arctic sea ice is shrinking as the ocean heats up.
The amplification of arctic warming in the past two decades is a major concern for climate scientists. The increase in Arctic temperatures is nearly twice as fast as the global average, a phenomenon called Arctic amplification. This finding is in line with both theoretical understanding of the Earth’s climate system and climate model projections of global warming. There are many factors contributing to this phenomenon. One of these is increased Arctic heat transport through ocean and atmospheric circulation. Another contributor is the loss of snow and ice cover.
This reduced snow and ice cover reflect solar radiation back into space, thus warming the Arctic.
Provided by Antonio Westley
Disclaimer: This article is meant to be seen as an overview of this subject and not a reflection of viewpoints or opinions as nothing is definitive. So, make sure to do your research and feel free to use this information at your own discretion.