Tree rings capture an abrupt irreversible shift in east Asia's climate

November 26, 2020

The abrupt shift to hotter and drier conditions over inner East Asia is unprecedented and may herald an irreversible shift to a new climate regime for the region, according to a new study. The findings reveal a positive feedback loop fueled by declining soil moisture, which may have nudged the area's climate over an important tipping point. Extreme heatwaves and droughts are two of society's most pressing concerns as climate change driven by human activity continues unabated. Global warming has already led to recent and rapid shifts in climate worldwide, including inner East Asia, which has experienced some of the most pronounced heatwave-drought concurrences in recent decades. It's thought that such abrupt and substantial changes represent the crossing of critical thresholds within the climate system and signal irreversible shifts from one climate regime to another. But, identifying tipping points and new climate norms is difficult; not only does it require a thorough understanding of a region's natural climate variability over timescales that often exceed available records, regime shifts are likely triggered by complex interactions between a variety of poorly understood factors in the highly dynamic climate system. To determine whether the heatwave-drought trends observed in inner East Asia indeed exceed the range of natural climate variability, Peng Zhang and colleagues used tree-ring data to reconstruct a record of heatwave frequency and soil moisture for the region spanning the past 260 years. Zhang et al. found that the rise in concurrent heatwave-drought events over the last two decades is unique and beyond the natural variability revealed by their centuries-long record. What's more, the authors demonstrate that the rise in heatwave-drought events may be caused by a positive feedback loop between decreasing soil moisture and increasing surface warming - a pattern that's potentially the start of an irreversible trend that's likely to produce more frequent and severe events. While much remains to be understood about the occurrence and mechanisms of climate regime shifts, developing trustworthy long-term climate records is crucial in detecting changes in the interactions of climate variables, discovering past shifts and predicting tipping points of potential future shifts, write Qi-Bin Zhang and Ouya Fang in a related Perspective.
-end-


American Association for the Advancement of Science

Related Climate Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Climate Insights 2020: Climate opinions unchanged by pandemic, but increasingly entrenched
A new survey provides a snapshot of American opinion on climate change as the nation's public health, economy, and social identity are put to the test.

Climate action goes digital
More transparent and accessible to everyone: information and communication technologies bring opportunities for transforming traditional climate diplomacy.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

How aerosols affect our climate
Greenhouse gases may get more attention, but aerosols -- from car exhaust to volcanic eruptions -- also have a major impact on the Earth's climate.

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

How trees could save the climate
Around 0.9 billion hectares of land worldwide would be suitable for reforestation, which could ultimately capture two thirds of human-made carbon emissions.

Climate undermined by lobbying
For all the evidence that the benefits of reducing greenhouse gases outweigh the costs of regulation, disturbingly few domestic climate change policies have been enacted around the world so far.

Climate education for kids increases climate concerns for parents
A new study from North Carolina State University finds that educating children about climate change increases their parents' concerns about climate change.

Read More: Climate News and Climate Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.