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New Research Tool Gives More Accurate Picture of Global Temperature Shifts

A dataset of global temperature shifts going back to the 1800s provides a new tool for scientists to use in studying climate change.

(CN) — As climate change receives more attention across the globe, it’s crucial that scientists and researchers have the most accurate data possible on global temperatures. Researchers out of China's Sun Yat-Sen University released Thursday a newly merged global surface temperature dataset to assist in climate research.

Part of the difficulty in creating an accurate picture is the lack of observational data in some regions such as the Arctic or high-altitude areas like the Qinghai-Tibetan plateau, making it difficult to assess temperature variations adequately and consistently across the globe.

The study published in the journal Advances in Atmospheric Sciences brings together climate measurements from the 1850s to 2018 and reconstructed global land surface temperature datasets. 

Researchers used data from the China Merged Surface Temperature (CMST) and the sea surface temperature dataset from the National Oceanic and Atmospheric Administration. Merging the data provided a new dataset of land and sea surface temperatures.

The resulting dataset is the CMST-Interim, a global monthly surface temperature dataset spanning from 1854 to 2018, which includes improved coverage of the Earth's surface, with 90% of the globe included from the 1950s onward. 

The study provides evidence there was a consistent increased warming trend compared with previous estimations, which closely matches the available observational data and updated simulations covering the past two decades.

"The global surface temperature is one of the most important and accurate essential climate variables in the Earth system, yet there are still a number of discrepancies among the evaluation of magnitude of global warming," said paper author Qingxiang Li, professor in the School of Atmospheric Sciences and Key Laboratory of Tropical Atmosphere-Ocean System, Sun Yat-Sen University, and in the Southern Laboratory of Ocean Science and Engineering in China.

By merging land and sea data and analyzing previous research using the combined dataset, researchers were able to provide context to discrepancies such as the “hiatus” period, when global warming appeared to slow from 1998 to 2012, especially for observations of high-latitude regions such as the Arctic. 

The researchers found that the existing datasets overestimated surface temperature anomalies prior to the 19th century, yet underestimated surface temperature anomalies in the 21st century — explaining the appearance of the hiatus period.

"The CMST-Interim shows a significantly increased warming rate of the global surface temperature compared to the original dataset,” the researchers stated.

Next, the team plans to continue improving and testing CMST-Interim, with a specific focus on improving the assessment of sea ice surface temperatures and eventually upgrade CMST-Interim to a new version of CMST.

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