The term natural disaster is defined as “a sudden and terrible event in nature that usually results in serious damage and many deaths.” According to the World Economic Forum, the most common natural disasters include floods, storms, earthquakes, extreme temperatures, landslides, droughts, wildfires, and volcanic activity. How does climate change impact each of these extreme events?
Floods are the most frequent natural disaster and have impacted every U.S. state and nearly every country. The connection between floods and climate change comes down to a few ways that climate change is impacting water. First, higher temperatures lead to increased levels of evaporation, creating denser clouds that hold more water. This eventually leads to heavier precipitation that can cause flooding. Second, more frequent and intense storms such as hurricanes can lead to floods. Finally, higher sea levels due to melting glaciers can also prompt coastal flooding.
Floods can also be exacerbated by how humans manage waterways and spur urbanization.
Storms are impacted by climate change in the same way that some floods are, via the effect that higher temperatures have on evaporation and subsequent precipitation. With clouds holding increased amounts of water vapor, more powerful storms develop.
The connection between earthquakes and climate change is slightly less straightforward, and certainly less influential. Most earthquakes occur when tectonic plates within the Earth’s crust change or move. Many things can lead to this, but where climate change comes into play is once again related to water. Earthquakes can be triggered or prevented by variability in stress on a fault between tectonic plates. Stress on these faults is impacted by surface water from rain or snow. When there is heavier rainfall, this precipitation and any subsequent flooding increases stress and decreases seismicity. When the season dries up and there’s less water, the weight on the Earth’s crust decreases and this can lead to microseismicity.
As of now, the majority of the connection between earthquakes and climate change is with microseismicity, or tiny earthquakes, which have magnitudes of less than zero and are so small that humans can’t feel them. While additional connections can be made, such as impacts from pumping groundwater during droughts, connections between larger earthquakes and climate change have largely not been proven, though the rapid movement of glaciers has also been shown to cause glacial earthquakes.
4 Extreme Temperatures
Climate change can lead to both extreme high temperatures and extreme low temperatures. The connection with extreme high temperatures is more intuitive — greenhouse gases are being trapped in the atmosphere and this leads to warming. However, the connection to extreme low temperatures can be harder for some people to make. Lower temperatures in some regions are a result of the polar vortex being warmer, causing it to weaken and dip down further than it normally would, bringing with it colder temperatures. This is further exacerbated by impacts to the jet stream that change the pattern of where and when hot and cold temperatures typically occur. These two combined have led to hotter summers and harsher winters in some areas.
Landslides are connected to rainfall as well. Due to climate change’s impact on evaporation and precipitation, more frequent and intense rainfall events can lead to more landslides.
On the other side of the water spectrum are droughts, though they result from the same process. Droughts are a natural part of the climate cycle, but climate change is making them more frequent, severe, and prolonged. While higher levels of evaporation lead to eventual severe rainfall, in some regions, this shift means drier conditions due to the loss of the evaporated water, which can lead to drought and dried out soils and vegetation. With climate change, places that are traditionally dry are becoming drier through the higher levels of evaporation and places that are traditionally wet are becoming wetter through the higher levels of rainfall that result.
Wildfires are a consequence of the drier conditions caused by climate change in some areas. The wildfire season is much longer than in previous years and the number of wildfires per season has tripled. Severe heat and drought provide fuel for fires through drier soils and vegetation that is more flammable. Additionally, due to warmer temperatures, snowpacks are melting earlier, meaning that forests are drier for longer periods of time and increasingly at risk of fires.
8 Volcanic Activity
Similar to earthquakes, volcanic activity has a less direct relationship with climate change. Volcanoes do contribute to changes in Earth’s atmosphere through spewing CO2, aerosols, ash, and metals into the atmosphere, but they have a net cooling effect. This is due to the impact that aerosols have on cooling versus warming.
On the flip side, there is some evidence to suggest that climate change could increase eruptions in a similar way that they impact seismic activity, through lessening the pressure on the Earth’s surface. In this case, this decreased pressure causes more hot magma to come in contact with aquifers, which triggers eruptions. Additionally, melting glaciers are exposing more volcanoes.