Scientists are discovering a tighter link between global warming and shifting weather patterns. In the early 2000s, a new school of climate-science study evolved, focusing on the human impact on extreme weather events like floods, heatwaves, droughts, and storms. All of this is referred to as “extreme event attribution,” and the field has gained traction not only in the scientific community but also in the media and popular imagination. These researches have the ability to connect the seemingly abstract topic of climate change to extreme weather to personal and actual weather experiences.
Heat and Drought
Heatwaves have serious consequences, including death, as a result of both temperature and humidity, especially if they last longer than two days. With monthly and annual temperature records being broken, it’s likely that human-caused global warming is increasing the frequency of extreme heat occurrences.
Higher temperatures increase evaporation, which dries out the soil in the summer, exacerbated drought in many locations.
Storms and Floods
Rainfall intensifies when higher evaporation leads to more moisture in the atmosphere. We now know, for example, that due to human-induced climate change, Hurricane Harvey’s rainfall was 15% more severe and three times as likely to occur.
As temperatures rise, we should expect an increase in the frequency of Category 4 and 5 storms.
While scientists are divided on whether climate change has resulted in an increase in hurricanes, they are convinced that rising sea levels have resulted in stronger storm surges and floods.
The expansion of warming oceans, induced by human-caused global warming, accounts for roughly half of the rise in sea level since 1900.
Snow and frigid Weather
A warmer atmosphere holds more moisture, which can contribute to recording snowfall. It may sound contradictory, but climate change may be connected to an increase in snowfall during winter storms.
Keep in mind that the warmer the atmosphere, the more moisture there is. As a result, when the temperature drops below freezing, the snowfall might be record-breaking.
Scientists are also looking into the possibility of a link between the warming Arctic and cold spells in the eastern US. The theory is that as the Arctic warms, the jet stream weakens, allowing freezing polar air to drift further south.
Over 350 peer-reviewed research on weather extremes around the world has been published, ranging from heatwaves in Sweden and droughts in South Africa to flooding in Bangladesh and hurricanes in the Caribbean. As a result, there is growing evidence that human activity is increasing the danger of certain types of climate change to extreme weather, particularly those related to heat.
Carbon Brief has mapped
– to the best of our knowledge
– every extreme-weather attribution study published to date to see how the evidence stacks up on this fast-moving topic.
According to Carbon Brief’s analysis, human-caused climate change has made 70 percent of the 405 extreme weather events and trends featured in the map more frequent or severe.
– Climate change reduced the likelihood or severity of 9% of events or trends, implying that 79 percent of all events had some human impact. The remaining 21% of occurrences and trends were either inconclusive or had no clear human influence.
– Climate change made the event or trend more frequent or severe in 92 percent of the 122 attribution studies that looked at excessive heat around the world.
Human activities increased the likelihood or severity of the event in 58 percent of the 81 research that looked at rainfall or flooding. It’s 65 percent for the 69 drought occurrences evaluated.
This is the fourth annual update (see endnote) to include additional studies since it was first published in July 2017. Its purpose is to act as a tracker for the field of “extreme event attribution,” which is still developing.
Extreme weather types
357 unique scholarly papers or fast investigations cover the events and trends depicted on the map. These have been divided apart where single research covers numerous events or locales.
When the evidence from the last 20 years is combined, studies of excessive heat (33 percent), rainfall or flooding (20 percent), and drought (11 percent) dominate the literature (17 percent ). More than two-thirds of all published studies are made up of these three categories (70 percent ).
The number of extreme occurrences analyzed has increased dramatically over the last 10-15 years, as shown in the graph below. Because the writing and peer-review procedure for journal papers might take months, official studies usually take a year or more after the incident.
The majority of the studies in this collection were first published in the Bulletin of the American Meteorological Society’s annual “Explaining Extreme Events” special issue (BAMS). Each bumper volume usually comprises 15-30 peer-reviewed analyses covering the preceding year’s events.
From climate change to extreme weather event type and year, the number of attribution studies has increased. Note that the total number of incidents in 2017 decreased because the Bulletin of the American Meteorological Society special report for that year was published in early 2018 instead of late 2017. Carbon Brief created this graph with Highcharts.
The majority of the extreme weather categories are self-explanatory, but “storms” and “oceans” require some explanation.
Tropical cyclones, such as hurricanes and typhoons, and extratropical storms are both included in the “storms” category for convenience of presentation. The category “oceans” includes By clicking on the category titles at the top of the chart, you may see certain sorts of events.
By extreme weather event type and year, the number of attribution studies has increased. Note that the total number of incidents in 2017 decreased because the Bulletin of the American Meteorological Society special report for that year was published in early 2018 instead of late 2017. Carbon Brief created this graph with Highcharts.
The majority of the extreme weather categories are self-explanatory, but “storms” and “oceans” require some explanation. Tropical cyclones, such as hurricanes and typhoons, and extratropical storms are both included in the “storms” category for convenience of presentation.