Nav: Home

Human-caused climate change played limited role in Beijing's 2013 'airpocalypse'

April 25, 2019

In January 2013, a suffocating, poisonous haze hung over Beijing for four days. The record high levels of fine particulate matter in the air caused airports to close and thousands of coughing, choking citizens to seek hospital care.

Although the particulate matter that filled the winter skies resulted from both human and natural emissions, a new Northwestern University study concludes that human-caused climate change played only a minor role in the air's stagnation.

The study, which used computational simulations of climate, is one of the first to tie an air quality episode to human-caused climate change. This type of research is part of the growing subfield of climate science called "detection and attribution of extreme events," which assesses how human emission of greenhouse gases may have contributed to the occurrence and/or severity of a particularly impactful event.

"Typically, single event detection and attribution work is performed on 'charismatic' extreme weather events, such as hurricanes, heat waves and droughts. Here, we perform the analysis on something less glamorous -- still air over Beijing," said Northwestern's Daniel Horton, the study's senior author. "Our work applies detection and attribution methods to a less glamorous yet highly impactful -- particularly for public health -- meteorological phenomenon."

The lingering haze -- that was signature to Beijing's 2013 "airpocalypse" and other smog events -- requires two factors: the emission of pollutants and still air that allows the pollutants to build. Beijing's coal-burning power plants and 5 million motor vehicles are responsible for much of the city's pollution. Horton and first author Christopher Callahan aimed to discover if human-caused climate change played a role in the meteorological conditions that led to the still air.

"Even though we found that climate change has not had a major influence on winter air quality over Beijing to date, this work adds some meteorological diversity to recent examinations of links between climate change and individual extreme events," said Callahan, a former undergraduate student in Horton's lab, who led the research.

The study will publish April 30 in the Journal of Geophysical Research: Atmospheres. Horton is an assistant professor of Earth and planetary sciences in Northwestern's Weinberg College of Arts and Sciences. Callahan is currently a Ph.D. candidate in geography at Dartmouth College, where he studies climate modeling and impacts.

To explore the meteorological conditions underlying the airpocalypse, the team compared climate simulations: one set of model experiments included the current trend of human-caused climate change and one set as if human-made climate change did not exist. The researchers found that, in both scenarios, meteorological conditions conducive to poor air quality in Beijing still occurred.

The simulations did indicate, however, that if human-caused climate change continues along the same trend, it might lead to more extreme air quality events. Already, 4.2 million deaths worldwide are caused by air pollution, according to the World Health Organization. Many of these deaths result from pollution-related respiratory diseases, heart disease or stroke.

"We found that climate change was not the most important factor in shaping air quality during Beijing's past winters. Natural atmospheric fluctuations were conducive to air quality degradation," Callahan said. "However, we found a small human fingerprint that could increase into the future."

Even though human emission of greenhouse gases only played a minor role in Beijing's past poor winter air quality events, Callahan contends that humans can greatly improve air quality by cutting air pollutant emissions. Such reductions are often coincident with greenhouse gas reductions. Thus, not only would reductions help curtail global climate change, they also would have the added benefits of clean air and fewer pollution-related illnesses.

"Climate change mitigation, at its core, requires greenhouse gas emission reductions," he said. "If we can do that while also reducing pollutant emissions, it's a win-win."
-end-
The study, "Multi-index attribution of extreme winter air quality in Beijing, China," was supported by the National Science Foundation (award number CBET-1848683) and the Ubben Program for Climate and Carbon Science at Northwestern.

Northwestern University

Related Climate Change Articles:

The black forest and climate change
Silver and Douglas firs could replace Norway spruce in the long run due to their greater resistance to droughts.
For some US counties, climate change will be particularly costly
A highly granular assessment of the impacts of climate change on the US economy suggests that each 1°Celsius increase in temperature will cost 1.2 percent of the country's gross domestic product, on average.
Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Climate change scientists should think more about sex
Climate change can have a different impact on male and female fish, shellfish and other marine animals, with widespread implications for the future of marine life and the production of seafood.
Climate change prompts Alaska fish to change breeding behavior
A new University of Washington study finds that one of Alaska's most abundant freshwater fish species is altering its breeding patterns in response to climate change, which could impact the ecology of northern lakes that already acutely feel the effects of a changing climate.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
The psychology behind climate change denial
In a new thesis in psychology, Kirsti Jylhä at Uppsala University has studied the psychology behind climate change denial.

Related Climate Change Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...