The reason why extreme weather happens is because human activity is causing rapid changes to our global climate that are contributing to extreme weather conditions. When fossil fuels are burned for electricity, heat, and traps solar radiation, is released into our atmosphere. Over the past century, massive increases in carbon dioxide, methane, and other greenhouse gas emissions have caused the temperature on our planet to rise. That spike in global temperatures is fueling climate disasters that will only get worse unless we take action. Experts warn that we are running out of time to dramatically cut pollution to avoid climate catastrophe.
Extreme events are occurrences of unusually sever weather or climate conditions that can cause devastating impact on communities and agricultural and nature ecosystems. A common example is the number of consecutive days over 100 F, which can be used to quantify heat waves. This portion of the Climate Hubs website expands on the types of extreme events that impact the different climate hub regions. Climate change is expected to worsen the frequency, intensity, and impacts of some types of extreme weather events. There can be as many as 40,000 thunderstorms each day around the world. They are most common in the U.S., where they can produce tornadoes, floods, lightning and damaging winds. A thunderstorm is classified as “severe” when it contains one or more of the following: hail one inch or greater, winds gusting in excess of 50 knots (57.5 mph), or a tornado. Thunderstorms are most likely in the spring and summer months and during the afternoon and evening hours, but they can occur year-round and at all hours.
Much about tornadoes remains a mystery. They are rare, unpredictable and deadly. The U.S. has more tornadoes than anywhere else in the world. Tornadoes occur in many parts of the world, including Australia, Europe, Africa, Asia, and South America. Even New Zealand reports about 20 tornadoes each year. Two of the highest concentrations of tornadoes outside the U.S. are Argentina and Bangladesh. The truth is that we don't fully understand. The most destructive tornadoes occur from supercells, which are rotating thunderstorms with a well-defined radar circulation called a mesocyclone. (Supercells can also produce damaging hail, severe non-tornadic winds, frequent lightning, and flash floods.) Tornado formation is believed to be dictated mainly by things which happen on the storm scale, in and around the mesocyclone.
https://www.climatehubs.usda.gov
https://www.nssl.noaa.gov
https://earthjustice.org