Industrial-era pollution and warming reshape Tibetan lake after 1,000 years of climate swings Gaby Clark Scientific Editor Robert Egan Senior Editor The Tibetan Plateau, together with the Hindu Kush–Karakorum–Himalaya region, has more snow and ice than any other region on Earth apart from the polar regions. As a result, this high-altitude region is particularly sensitive to climate change, making it especially important in analyzing its impacts. In recent years, researchers from the DFG Research Training Group TransTiP have been investigating changes in the region's geo-ecosystems.

"Our results decipher the complex interplay of natural and anthropogenic climate drivers, to which even lake ecosystems in remote regions react highly sensitively, and whose impacts are archived in lake sediments. Furthermore," says Professor Antje Schwalb, head of the Institute of Geosystems and Bioindication and spokesperson of the DFG Research Training Group TransTiP. "I am pleased that the curiosity and perseverance with which our former doctoral researcher Wengang Kang advanced this topic have now been rewarded with a publication in Nature Communications." Reconstructing past climate and environmental changes To investigate how natural and human-induced climatic factors have shaped the lake ecosystems on the Tibetan Plateau, the researchers used lake sediments to reconstruct environmental and ecological changes in Nam Co, the third-largest lake in the region.

The lake, which covers an area of around 2,000 square kilometers (772 square miles), is situated at an altitude of 4,720 meters (15,486 feet) above sea level. Geochemical indicators, including titanium, were used to reconstruct fluctuations in South Asian monsoon rainfall, while fossilized diatoms and pigments documented the long-term ecological responses within the lake. "This approach provided a detailed overview of how the lake's ecosystem responded to past climate and environmental changes," says Dr.

Wengang Kang, a former doctoral researcher in the TransTiP Research Training Group and lead author of the study. In addition, the international research team employed a so-called "climate fingerprinting" approach, led by Céline Bonfils at Lawrence Livermore National Laboratory, U.S. To this end, the researchers analyzed simulations from several Earth system models that replicate climate trends over the past 1,000 years.

This enabled them to distinguish natural climate fluctuations from changes caused by external influences. This made it possible to determine the extent to which factors such as volcanic eruptions, changes in the Earth's orbit, greenhouse gases and man-made air pollution have contributed to the observed climate fluctuations. Less ice, more glacial meltwater The study shows that two major climatic processes in particular have had a decisive influence on the water balance of the Tibetan Plateau and the lake ecosystems over the past 1,000 years.

The first process relates to temperature. Before industrialization, volcanic eruptions repeatedly cooled the climate, thereby influencing the ecological conditions of the lakes. Since the 19th century, however, global warming caused by greenhouse gases has fundamentally altered this mechanism: The lake is covered by ice for shorter periods, and more glacial meltwater flows into it.