Last year was the hottest year on human record. That heat fueled several events – Heat waves, rainfall, fires – Reach unprecedented scale. And their influence still reverberates.
Record-breaking wildfires in Canada last year Smoke rises in winter And began to regain strength. Hurricane activity is likely in the Atlantic Ocean Above normal In part last year an unusual amount of heat was absorbed by the ocean. Heat waves and warm winters in many parts of the world are setting the stage for more intense heat this year, increasing the likelihood that this year will be even hotter than last year. Already like place Finland, MexicoAnd India Experiencing heatwaves before their respective summers.
Different types of disasters can also be compounded. Wildfires can uproot trees and burn ground cover, eroding the landscape and leaving it Vulnerable to landslides. Years of drought dry out the soil, compacting it and making it impervious so when heavy rains begin, they cause more widespread flooding.
Weather has natural variability and includes extremes. But mankind’s output of greenhouse gases is increasing global average temperatures and thus increasing the likelihood and intensity of many types of extreme weather events.
The increasing frequency and intensity of weather extremes is creating a regime in which many disasters are isolated, not single events but build on the foundations of earlier heat waves, droughts, wildfires and rainfall.
It’s not just one disaster after another; It is extreme events that push subsequent disasters to a greater destructive potential. This creates a cumulative effect that does not necessarily reset year after year. And more people are experiencing these combined effects. By a guess, more than that 90 percent of the world’s population Changes in the climate system as well as changes in water and land use are leading to a greater risk of combined heat waves and droughts. Add to that a growing population that continues to build in vulnerable areas.
The result is more frequent, dangerous, and costly disasters.
Understanding how extremism can breed extremes can help people anticipate and prepare for future threats. But right now, scientists are still struggling to gather the basic data they need to figure out how the extremes affect each other.
Explain how past extremes can affect present extremes
There are many ways that disasters can affect each other. An example is how extreme droughts can lead to more extreme floods. The western United States is still reeling from one A multi-decade droughtAt least the worst dry spell 1,200 years. A lack of rain combined with rising average temperatures dries out soil and vegetation as warmer air can draw out more moisture.
Low soil moisture causes the soil to compact, making it less able to hold water. Withered grasses, shrubs and trees also do little to retain rainfall with their roots.
So when torrential rains like California’s Atmospheric Rivers earlier this year, storms dump more water on land than it can absorb, causing more flooding. The cycling between droughts and floods creates a phenomenon that some scientists describe as weather whiplash.
Wildfires can then exacerbate this. Infernos bring down trees and other plants that anchor the ground with their roots, so when heavy rains fall, they trigger dangerous landslides. That was clearly illustrated 2018 in Montecito, California. In previous years, a wet winter resulted in an adequate early-season flowering that soon dried up during the hot, dry spring and summer months. Those who burn grass and bushes and fuel Thomas Fire, which burned over 280,000 acres, driven by brisk monsoon winds. At the time, it was the largest wildfire in California on record. Then on January 9, 2018, after a heavy rainstorm, residents of Montecito woke up to mudslides. 15 feet up Sliding high towards them. The landslide killed 23 people and destroyed more than 400 houses.
Another example we’re seeing this year is how warm ocean temperatures can increase over time and create raw material for hurricanes.
In 2023, the temperature of the Atlantic Ocean will reach a level never before measured by humans. Hurricanes need surface water to be at least 80 degrees Fahrenheit, but they also need stable winds over the ocean. El Niño, the warm phase of the Pacific Ocean temperature cycle, was in full swing last year. This raises global temperatures, but it also increases wind shear over the Atlantic, which limits hurricane formation. This has allowed the Atlantic Ocean to be charged with more heat, resulting in higher water temperatures this year. El Niño is on its way to La Niña this year, with winds settling over the Atlantic, setting the stage for this year. Hurricane season is above normal. NOAA is forecasting up to 25 named storms and seven major hurricanes.
The effects of compounding extremes can be far-reaching and complex
These intersecting extremes have real-world consequences. Beyond the direct impact on people’s lives and property, one of the most consequential impacts is food security.
Extreme heat, drought and excess moisture are all factors that can cause crop failure, but when they combine, these events can take a bigger bite out of crop yields. Of particular concern is a “hot drought,” where high temperatures combine with below-normal precipitation levels, a particularly stressful combination for plants. This compounding can be extreme in places like India, Ethiopia, and the United States Reduce yield up to 30 percent.
“Because it’s getting warmer on average, droughts tend to be warmer on average,” explained Cory Lesk, a researcher at Dartmouth College studying climate impacts. Meanwhile, Heavy rain events is becoming more common. Instead of being evenly spread over the growing season, precipitation is falling Fewer, more severe cases. Not only does this cause flooding, it also means plants don’t get the water they need during monsoons.
But Lesk notes that there are reasons to push in the other direction as well. Climate change could mean longer growing seasons for crops in some parts of the world, leading to more abundant harvests. More carbon dioxide in the atmosphere may help plant growth somewhat. And farming techniques are improving with a wider range of tools such as hardy crop varieties, precision fertilization and early disease detection. “The strongest trend in yield growth in general is the technological trend,” says Lesk.
Compounding weather extremes aren’t just coming for our bellies; They are rifling through our wallets. Insurance provides a shining example. In the United States, insurers are shedding customers or leaving states entirely because their risk portfolios can bear the coverage and pricing regulations they face in some states. Losing insurance can then affect more fundamental decisions such as where people should live and places they should leave.
For insurers, one challenge is that it is becoming increasingly difficult to predict how the various extremes will intersect and play out. According to Intergovernmental Panel on Climate Change Special Report on Ocean and Cryosphere (frozen part of the planet), composite disasters “exemplify deep uncertainty because a lack of information often prevents assessment of risk probabilities and consequences from composite events.”
Although cosmic storms and raging infernos are major events, they are less common than normal natural phenomena, so there are not many robust measurements over time that explain how they are changing. Most of the best data on hurricanes, for example, date only to the 1970s, when new high-resolution satellite instruments entered orbit. Insurance companies use historical records to gauge risk, but without good numbers, it’s hard for them to create a baseline understanding of how last year’s drought will affect landslides this year. Even less certain is how these variables will align in the future as average temperatures rise.
Additional complications are that climate change may produce unexpected fundamental changes in the fundamental mechanics of extreme weather patterns. For example, there may be more warming West Antarctic ice to enter a self-propagating cycle of decline. “[C]Limiting drivers contributing to compounding events may exceed the tipping point in the future,” according to the report.
Faced with these unknowns, it is wise to invest in measures that can save lives. This includes upgrading infrastructure to make it more resilient, building more robust forecasting models and putting in place early warning systems to get people out of harm’s way. But to prevent relentless warming of the planet, mankind must zero in on its greenhouse gas emissions. If not, there will be more disaster ahead.
