In recent years, extreme heatwaves have swept across multiple countries and regions. With global warming continuing, studies suggest that we will face more frequent and intense heatwaves in the future.
As global value chains become increasingly interconnected, economic losses in regions affected by extreme heatwave events will spread to other economies through supply chains, potentially impacting global energy supply, product production, and food security. Five years ago, Guan Dabo, a professor in the Department of Earth System Science at Tsinghua University, had the idea of conducting interdisciplinary research to quantify the economic losses caused by extreme heatwave events.
Guan Dabo led his team to collaborate with the University of California, Irvine, and King's College London for three years. They broke down disciplinary barriers and successfully constructed an interdisciplinary disaster footprint model of "climate-health-economy." They assessed the global heatwave health risks and economic losses under climate change at the grid scale. On March 14, the related research findings were published in Nature.
This research provides decision-making references for China's climate adaptation and risk prevention. It also provides a scientific basis for targeted and collaborative climate governance globally.
Three years ago, extreme heat waves ravaged several cities in China. Even Harbin, Guan Dabao's hometown which is known as a "summer resort haven", didn't escape the scorching heat. The severe heat left a deep impression on Guan, who has been studying climate change for many years. He turned his attention to the impacts of extreme heat waves.
With global warming, the types of climate disasters are gradually increasing. Another key factor in Guan's choice of this "star" is that while typhoons, floods, and other climate disasters have received considerable research attention, extreme heat waves have been largely overlooked, especially their hidden impact on economic systems. "This paper's corresponding author, Guan Dabao, said in an interview with the China Science Daily.
Heat's Impact on Health and Economy
Extreme heat can have adverse effects on human health, including heatstroke, sleep disruption, chronic kidney disease, heart attacks, and even death. It can also affect worker attendance and productivity in hot environments, reducing effective working hours and output.
"Quantifying these economic losses is crucial for achieving multiple sustainable development goals related to well-being, decent work, economic growth, and poverty eradication," said Guan Dabao, who engaged with his PhD student Sun Yida on the topic, sparking his interest.
However, it was a daunting task.
This time, they needed to integrate multiple disciplines, something that had never been attempted in previous research. "Simply put, it's an Earth system science study coupled with socioeconomics. It's a huge challenge," said Guan.
Tsinghua University's Department of Earth System Science is responsible for the major task of developing a large Earth system model in the field of global geoscience. "Climate change simulation is our department's forte. But once climate parameters are simulated, how much impact they will have on human health or the economy has been a longstanding issue in academia," said co-first author Sun Yida in an interview with China Science Daily.
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Guan Dabo (left) supervising students; Sun Yida on the right, images provided by the interviewee.
The research team from the University of California, Irvine, is one of the most renowned teams in the field of global environmental health research. They specialize in evidence-based research on the impacts of climate parameters on health. Combined with the expertise of Dr. Wang Daoping's team at King's College London in researching the impacts on global trade, the three top-tier teams joined forces, pooling their respective strengths to embark on a collaborative journey.
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"It was an arduous and uncharted path," remarked Sun Yida. "To seamlessly link climate models with health and economic models, we made tremendous efforts. The teams from three different fields communicated relentlessly over three years, eventually breaking down the barriers between the models to present a complete chain."
Guan Dabao, who has published several papers in Nature and its sub-journals, was familiar with the submission process, but he did not expect to encounter a submission "predicament" this time.
This research article, integrating "climate system models, economic and environmental health models, and global trade models," was carefully polished by several co-authors. They confidently submitted it to Nature, but did not receive any peer review comments in a timely manner.
After communicating with the editor, they learned that they had difficulty finding "suitable" reviewers. This was because in academia, researchers who are well-versed in climate systems, economics, and environmental health are rare.
However, the Nature editorial team was very optimistic about this research. The article could not be shelved indefinitely, so the editor separately found scientists from these three fields and added two experts who specialize in cross-cutting models to review the article in order to ensure scientific rigor.
Five reviewers from completely different fields meant that the submission process would be very challenging. The submission cycle was very long, and the authors all experienced different levels of anxiety.
"At one point, a reviewer even suggested that we conduct a high-precision, long-term validation of the model. My colleague Dao Ping and I both wanted to give up and just change journals because the workload was too heavy and almost impossible to complete," Sun Yida was frustrated at the time and complained to his supervisor, Guan Dabao.
The research team held a workshop together to discuss the direction of the article. Ultimately, their pursuit of scientific truth rekindled their fighting spirit.
"Since the reviewer raised this issue, regardless of whether the article is published or not, we are motivated to make the model more accurate so that it can truly serve national development and contribute to global climate governance," said Sun Yida.
Prior to this, none of the three teams had done any related validation work. After collecting thousands of data points and comparing them with the model's results, the research team spent half a year specifically completing the model's validation.
The level of detail and the rigorous work demonstrated by the team in answering the questions left a deep impression on the reviewers. In the second round of peer review comments, the reviewers expressed their joy and appreciation, writing, "Well done!"
"A good research study not only provides a lot of important information for current development and makes important contributions to policy-making, but also has another very important aspect: leading new research areas and directions," said Wang Daoping in an interview with China Science Daily.
In the end, this article, which was full of sincerity, was published after a year and a half of submission, with over 5,000 words in the main text, over 100 pages of appendices, over 30 tables, and 12 figures.
Through the constructed "climate-health-economic" interdisciplinary disaster footprint model, the research team made significant discoveries.
The research revealed from multiple perspectives, such as labor health and economic industrial chains, that the economic cost of climate warming will show an exponential growth trend.
"The economic impacts of extreme weather in the future are staggering. Every degree of global warming will cause tens of trillions of CNY in economic losses. No country is immune to climate change, and when the impact on global supply chains is considered, different regions face serious economic risks," said Guan Dabao.
Among them, the economic losses in tropical small and medium-sized developing economies are the most severe. The impact of supply chain disruptions is more widespread, with a significant impact on manufacturing powerhouses such as China and the United States, resulting in economic losses of approximately 2.7% and 1.8%, respectively.
Due to the complex effects of multiple factors such as climate and environment, population dynamics, industrial economic structure, and international trade patterns, there are significant differences in the climate-economic loss sensitivity of different countries, and most of the rapidly rising economic losses will be borne by developing countries.
For example, Africa's greenhouse gas emissions account for less than 5% of the global total, but six countries, including Rwanda and Zambia, will be among the top ten in terms of economic losses by the middle of this century. In terms of health losses, countries such as Angola and Rwanda will have GDP losses of over 5%.
It should be noted that the negative impacts of extreme heat waves often exhibit complex and hidden characteristics and are transmitted iteratively in the global supply chain, making them difficult to quantify precisely in previous studies. "The climate disaster footprint model developed in this study reveals the cascading effects of global extreme heat waves on health losses through a supply chain溯源 tracking method, highlighting the necessity of global cooperation to mitigate and adapt to climate change," said Sun Yida.
"We are all on the same planet, and every country will be affected by the direct or indirect effects of climate change. Our research benefits not only China, but also the entire world," Lu Hui, one of the co-authors of the paper and a professor in the Department of Earth System Science at Tsinghua University, told China Science Daily.
Understanding which countries and industries are most vulnerable is crucial for developing effective and targeted adaptation strategies. Guan Dabao suggests establishing a climate change loss and damage fund from the perspective of the global value chain and providing targeted and goal-oriented technical support for the climate resilience of key vulnerability nodes, which will bring positive economic benefits on a global scale.
Information on related papers: https://doi.org/10.1038/s41586-024-07147-z
