Global Warming Blamed for Increasing Record-breaking Weather

A new study found that global warming is responsible for causing record-breaking weather and unprecedented climate events around the world. It turns out that Earth is on the edge of a new meteorological era, with climate change-related extremes far more likely to happen on a regular basis.

The research, published this week in Proceedings of the National Academy of Sciences, discovered global warming doesn’t just make extreme events more likely across large regions of the globe. It also contributes to the increased severity of such events. The study is part of a fairly new field of climate detective work. Scientists around the world are seeking to identify the extent of the human-caused climate change and its connection to damaging extreme events.

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Man-made Climate Change & Record-breaking Weather

Every time there’s an unusually intense downpour, heat wave, or drought, Noah Diffenbaugh and his research team inevitably receive hundreds of emails and phone calls. People want to know whether human-driven climate change had something to do with it. What’s their answer?

Diffenbaugh is a professor of Earth system science at Stanford’s School of Earth, Energy & Environmental Sciences. He and a group of Stanford colleagues have set out to outline a four-step “framework” that will help them test the involvement of global warming in record-setting weather occurrences.

Their latest paper is also the newest in an emerging field of climate science called “Extreme Event Attribution.” Scientists in this branch seek to study the influence of climate change on extreme weather events. They do that by combining statistical analyses of weather observations with progressively powerful computer models.

 “The question is being asked by the general public and by people trying to make decisions about how to manage the risks of a changing climate,” Diffenbaugh said. “Getting an accurate answer is important for everything from farming to insurance premiums, to international supply chains, to infrastructure planning.”

This recent branch of science is testing the limits of what we know about climate change. In the past, researchers and scientists notoriously avoided connecting record-breaking weather events with climate change. They often claimed such links could not be established due to the challenges of separating human influence from the natural instability of the weather. However, this field is rapidly changing.

The past decade has brought on an explosion of research. Therefore, scientists are now capable of releasing results within just a few weeks of a major weather event. Diffenbaugh, the lead researcher on this study, is also the Kimmelman Family Senior Fellow at the Stanford Woods Institute for the Environment.

Tell Tale Signs of Climate Change

The risk, evidently, is inappropriately associating an extreme event with climate change. However, the authors found a way to ensure this wouldn’t happen. The studying of a certain weather occurrence always starts with the assumption that global warming had played no role. It is the scientists’ job to use statistical analyses to prove whether that assumption is valid or not.

Diffenbaugh explained the approach is highly conservative. In fact, it follows the legal model of “innocent until proven otherwise”. By default, the research team considers the weather event was just a misfortune. Only a really high amount of evidence will suffice to assign blame to global warming. To test their framework, the authors applied it to the driest, hottest, and wettest weather events around the world.

Results showed that man-made global warming caused by emissions of greenhouse gases has increased the probability of the hottest events. The outcome was valid across more than 80 percent of Earth’s surface area for which researchers had useable observations. Diffenbaugh stated that the world is heading to the point where every record-breaking hot event on the planet features a detectable human fingerprint.

As far as the wettest and driest events goes, the study authors found similarly worrying results. Human influence on the atmosphere has heightened the odds across almost half of the area that has dependable observations. Given that precipitation is naturaly noisier than temperature, the signal was expectedly less clear.

The clearest signals observed by scientists are the increased probability of severely dry events in the tropics. This region is also where the team saw the largest increase in the odds of extensive hot events. The resulting combination poses real threats for vulnerable ecosystems and communities in the area.

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Test Cases

The Stanford research team includes several former students and postdocs of the university. They used the most recent individual events to develop the extreme event framework. The 2012-2017 California drought is one of the occurrences they focused on, as well as the catastrophic flooding in India in June 2013.

One of the major goals of the new study was to test framework’s ability to assess events in multiple regions of the world. The team also wanted it to extend beyond acute precipitation and temperature. These two factors have already been the focus of most event-attribution studies.

Arctic sea ice was among the most important test cases. According to reports of the past three decades, the Arctic sea ice has diminished by almost 40 percent during the summer season. The team members applied their framework to this record-low sea ice cover and found astounding statistical evidence that climate change influenced the severity of the sea ice measurements.

The multi-pronged approach comes with another perk. The framework can be used to study deeper than the weather conditions at the surface. The team was able to also observe the meteorological elements that lead to the formation of rare events. For instance, Diffenbaugh and his colleagues found that global warming had played an important part in the atmospheric pressure pattern, which occurred over Russia during the 2010 heat wave.

Flames from a wildfire approach trees on the edge of the airport in La Ronge, Saskatchewan July 5, 2015 in a picture provided by Saskatchewan Ministry of Environment contract pilot Corey Hardcastle. The Canadian military has been called in to help fight wildfires in the Western province of Saskatchewan, where 112 active fires have forced the evacuation of more than 13,000 people and threatened several remote towns on Monday. Picture taken July 5, 2015. REUTERS/Corey Hardcastle/Handout via Reuters

Takeaway

Diffenbaugh’s framework meets the need for accurate, quantitative event attribution. This scientific branch will only grow in the following years. A retrospective look at the historical data shows us without a doubt that climate change is happening. It also shows extremes are expanding in many areas of the globe. And whether they want or not, humans depend on the weather. They make many of their decisions – both short and long term – based on the weather. Therefore, it only makes sense that they would want to know if global warming is accelerating the occurrence of record-breaking weather events.

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William E. Eubanks
 

I'm one of the main writers on the site; mostly dealing with environmental news and ways to live green. My goal is to educate others about this great planet, and the ways we can help to protect it.

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