Climate models

Tibetan Plateau may warm faster in future than climate models predict

In recent decades, the Tibetan Plateau, called “the roof of the world”, has warmed faster than the world average.

Projected future warming of the Tibetan plateau in the CMIP5 ensemble. The thick lines indicate the multi-model ensemble means, and the shadows indicate the 90% model intervals, derived from the raw model output. Dashed lines indicate constrained projections based on the result of the assignment. Blue and red represent a medium (RCP4.5) and high (RCP8.5) greenhouse gas emission scenario, respectively. Image credit: Wenxia Zhang.

The warming observed on the Tibetan plateau dating from the 1960s may be linked to human activities, in particular greenhouse gas emissions. The shelf may heat up faster in the future than what climate models predict, notes a new study recently published in the Environmental research letters newspaper.

Besides the Arctic and Antarctic, the Tibetan Plateau is made up of the largest volumes of ice and supplies water to dozens of major Asian rivers. But the rapid warming of the “Asian Water Tower” has significantly impacted the regional hydrological cycle and ecosystem services.

This has resulted in a notable decline in glaciers and geohazard-related disasters such as debris flows, glacial lake explosions and landslides.

A clear understanding of the past warming of the Tibetan Plateau, especially the underlying human influence, can help better anticipate and interpret future changes.

Tianjun Zhou, Study Leader and Corresponding Author, Senior Scientist, Institute of Atmospheric Physics and CAS Center of Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences

Zhou is also a professor at the University of the Chinese Academy of Sciences.

Zhou and his colleagues used CMIP5 – an archive of extended climate models, in which historical simulations are forced by distinct external influences – to unravel and measure the relative contributions of various external influences in the observed warming.

The researchers used an ideal fingerprint detection and attribution analysis to show that human impact is the main driver of the observed warming of the Tibetan Plateau (1.23 ° C from 1961 to 2005), greenhouse gases. greenhouse specifically contributing around 1.37 ° C, which was somewhat offset by anthropogenic aerosols.

Through a quantitative comparison of observations and modeled responses, attribution analysis shows that the CMIP5 ensemble and current global climate models underestimate the anthropogenic warming trend taking place on the Tibetan Plateau.

The researchers took this into account and corrected future projections using the attribution result as an observation constraint. They found that the Tibetan Plateau will likely heat up faster than expected in the future.

For example, in a medium carbon emission scenario (RCP4.5), the Tibetan Plateau is expected to warm by 2.25 ° C and 2.99 ° C in the medium term (2041-2060) and late 21st century (2081-2100), which are respectively 0.24 ° C and 0.32 ° C warmer than the uncorrected projections. This implies a greater loss of glacial mass and increased risk of geohazards in the Asian water tower.

Wenxia Zhang, second author of the study, Institute of Atmospheric Physics, Chinese Academy of Sciences

Journal reference:

Zhou, T., et al. (2021) Anthropogenic warming of the Tibetan plateau and future constraint projection. Environmental research letters. doi.org/10.1088/1748-9326/abede8.

Source: http://english.iap.cas.cn/


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