Submission + - Global Warming Since 1997 Underestimated by Half
Layzej writes: A new paper shows that global temperature rise of the past 15 years has been greatly underestimated. The reason is that the weather station network covers only about 85% of the planet. Satellite data shows that the parts of the Earth that are not covered by the surface station network, especially the arctic, have warmed exceptionally fast over the last 15 years. Most temperature reconstructions simply omit any region not covered. A temperature reconstruction developed by NASA somewhat addresses the gaps by filling in missing data using temperatures from the nearest available observations. Now Kevin Cowtan (University of York) and Robert Way (University of Ottawa) have developed a new method to fill the data gaps using satellite data.
The researchers describe their methods and findings in this youtube video. "The most important part of our work was testing the skill of each of these approaches in reconstructing unobserved temperatures. To do this we took the observed data and further reduced the coverage by setting aside some of the observations. We then reconstructed the global temperatures using each method in turn. Finally, we compared the reconstructed temperatures to the observed temperatures where they are available... While infilling works well over the oceans, the hybrid model works particularly well at restoring temperatures in the vicinity of the unobserved regions."
The authors note that "While short term trends are generally treated with a suitable level of caution by specialists in the field, they feature significantly in the public discourse on climate change."
The researchers describe their methods and findings in this youtube video. "The most important part of our work was testing the skill of each of these approaches in reconstructing unobserved temperatures. To do this we took the observed data and further reduced the coverage by setting aside some of the observations. We then reconstructed the global temperatures using each method in turn. Finally, we compared the reconstructed temperatures to the observed temperatures where they are available... While infilling works well over the oceans, the hybrid model works particularly well at restoring temperatures in the vicinity of the unobserved regions."
The authors note that "While short term trends are generally treated with a suitable level of caution by specialists in the field, they feature significantly in the public discourse on climate change."
