Are Extreme Weather Events Becoming More Frequent Globally?

Check out this answer from Consensus:

The evidence from recent research strongly suggests that extreme weather events are becoming more frequent globally. The increase in extreme precipitation and temperature events, along with the projected rise in extreme El Niño occurrences, highlights the urgent need for comprehensive climate action. As global temperatures continue to rise, understanding and preparing for the increasing frequency of extreme weather events will be critical for minimizing their societal impacts.

The frequency and intensity of extreme weather events have significant implications for societies worldwide. As global temperatures continue to rise, understanding the trends in extreme weather events is crucial for developing effective mitigation and adaptation strategies. This article explores whether extreme weather events are becoming more frequent globally, drawing on recent research findings.

Increasing Frequency of Extreme Precipitation

Recent studies indicate a notable increase in the frequency of extreme precipitation events. According to research, the total precipitation from the most intense events almost doubles per degree of warming, primarily due to changes in frequency rather than intensity1. This trend is observed in both climate models and real-world observations, suggesting that extreme precipitation events are becoming more common as the planet warms.

Trends in Extreme Temperature Events

In the United States, the frequency of extreme temperature events has been analyzed over a 41-year period. The findings reveal a clear increase in the risk of high-temperature extremes, although the results for rainfall vary with the season2. This suggests that while some types of extreme weather events, such as heatwaves, are becoming more frequent, the trends for other events like heavy rainfall may be more complex and season-dependent.

Impact of Global Warming on El Niño Events

The frequency of extreme El Niño events is also projected to increase significantly with global warming. Climate model simulations show that the frequency of these events doubles under the 1.5°C Paris Agreement target and continues to rise even after global temperatures stabilize3. This increase is driven by changes in oceanic conditions that sustain faster warming in specific regions, leading to a higher risk of extreme El Niño events in the future.

Are extreme weather events becoming more frequent globally?

Geert Jan van Oldenborgh has answered Uncertain

An expert from Royal Netherlands Meteorological Institute in Climate science

The answer depends on the type of extreme. Some types of weather events are becoming more extreme, such as heat waves or intense precipitation. Other are becoming less extreme, such as cold waves. And many fall in between: in some areas drought becomes more extreme, in others less so. The same holds for extreme snowfall.

Are extreme weather events becoming more frequent globally?

Walter Robinson has answered Near Certain

An expert from North Carolina State University in Climate science

Global warming is occurring, and it is nearly certain this warming is a consequence of increasing concentrations of heat-trapping (greenhouse) gases in Earth’s atmosphere. The build-up of these gases results from humans burning coal, oil, and gas and cutting down forests.

As the climate warms, not surprisingly we see more and more extreme heat events. It is nearly certain that extreme heat waves are becoming more frequent and that this change results from human-induced global warming.

Because extreme heat increases evaporation, soils and vegetation dry out faster when it is hotter. Thus, heat-waves are often associated with drought, and, at the same time, heat-waves become more severe when Earth’s surface dries out and vegetation wilts. Thus, it is likely that extreme droughts are becoming more frequent.

As temperatures increase, the amount of water vapor in the air, in moist conditions, increases (we say the atmosphere can “hold” more water vapor). This is a strong effect – roughly a 7% increase in water vapor (at saturation) for every degree Celsius rise in temperature. Because atmospheric water vapor converts to rain in clouds, as climate warms we expect the heaviest rains will become heavier. There is strong observational evidence that this is happening.

When water vapor condenses in clouds, it releases heat. This “latent” heat provides the fuel for many kinds o storms: tropical cyclones (hurricanes) and ordinary and severe thunderstorms. It is likely, therefore, that some storms are becoming more violent as climate warms – for example, the strengths of the strongest tropical cyclones appear to be increasing.

There are many other ways through which climate change can lead to increases in extreme weather. These are less certain than the direct effects of heat, drying, and water-holding capacity described above, however, and are the topics of very active research in climate science.

A recent review (focusing on the Continental U.S.) is here.

Are extreme weather events becoming more frequent globally?

Michael Wehner has answered Near Certain

An expert from Lawrence Berkeley National Laboratory in Climatology

This is a very broad question but the short answer is yes. Certain types of extreme weather have already become more severe because of human induced climate change. Other types of extreme weather are expected to become more severe as the climate warms, but changes have not definitely been found so far. The most obvious events affected by global warming are heat waves. Detectable and attributable changes in severe heat was published in 2013 by Seung-Ki Min and colleagues. Since then, there have been many studies of individual heat waves showing substantial human influence on the severity and frequency of such events. 

Likewise, increasing trends in extreme precipitation have also been detected and attributed to human changes to the composition of the atmosphere. This change is more subtle and is more evident in regions of high quality observations such as North America and Western Europe. 

Climate change affects different types of storms in different ways. Hurricanes and tropical cyclones have been extensively studied and found to have greater amounts of precipitation then there would have been had humans not interfered with the climate system. The first storm to be extensively studied in the context of climate was Hurricane Harvey which flooded the greater Houston area due to the copious amounts of precipitation. The flooding of New York and New Jersey by superstorm Sandy was exacerbated by increases in sea level because of climate change. While increases in hurricane precipitation are well-established, increases in the wind speed of intense hurricanes is also expected. However, these expected extreme wind speed increases are yet to be robustly detected due to signal to noise issues. Other classes of storms, such as extratropical cyclones and atmospheric rivers have also exhibited increases in precipitation although they are not as well studied. Very localized storms such as tornadoes, mesoscale convective systems and derechos are data limited, so formal detection and attribution has not yet been performed. 

The human influence on drought depends on what kind of drought you are talking about. Human increases in meteorological drought, a deficit in precipitation, has been weakly established in the Mediterranean region and may also be occurring in the southwest US and Mexico, although natural variability makes a definitive statement difficult. The human influence on agricultural drought, a deficit in soil moisture, is clearer in some regions as increased evapotranspiration has resulted from increases in seasonal average temperatures leading to drier soils.

Are extreme weather events becoming more frequent globally?

Kevin Trenberth has answered Near Certain

An expert from National Center for Atmospheric Research in Climate science

My answer has to be qualified, because all of the words here have multiple meanings. What is a “weather event”? What is an extreme? “More frequent” versus bigger?

For the most part weather as a whole continues much as it always has, with tremendous variability from day to day and year to year. The latter may be associated with the El Nino phenomenon, for instance, that can create prolonged (up to a year) distinctive weather patterns, altering storm tracks and creating wet spells, or droughts, in different regions. However, global climate change from increasing carbon dioxide and other greenhouse gases, arising from human activities, produces global warming. The latter is best thought of as global heating. Indeed temperatures are generally rising, but

most extra energy goes elsewhere: warming the oceans, melting ice, and evaporating moisture.  93% of the excess energy ends up in the ocean as ocean heat content which means the ocean expands and sea level rises.  Sea level also rises from melting land ice, including ice sheets of Greenland and Antarctica.  However, excess energy means more drying, 5 to 15% more water vapor in the atmosphere, stronger storms, and heavier rains, but where it is not raining, there are stronger heatwaves and drought, and more risk of wildfires.  The climate change effects intersect nonlinearly with weather (natural variability) so that effects move around in space and time, and can change from one extreme (heat) to another (flooding) very quickly.  Extremes generally worsen, nonlinearly amplifying damages and costs, producing “The straw that breaks the camel’s back” syndrome. That is, while the climate change may be a small, say 10%, effect on rainfall, the resulting deluge may exceed infrastructure thresholds and create catastrophic outcomes. At the same time, we often now have better warning systems, and loss of life and damage may be mitigated.

A key point here is that there are not more of these events (mostly) but rather the events that do occur are associated with greater extremes on the warm side for temperatures, and at both ends of the water cycle. Generally, there are fewer cold extremes.  In many places the observational evidence supports these claims, but the records are often not good enough or long enough with reliable data to demonstrate the results unequivocally in some places. Moreover, the very nature of the atmosphere is to form waves: for every cyclone there is an anticyclone, and for every warm outbreak there is a cold outbreak somewhere else. The result may be confusing unless one adopts a larger or even global view.