How does climate change fuel extreme weather?

Climate change can make heavy rains, heat waves, droughts and wildfires more severe and longer-lasting around the world .

1. Heavy rain

Every time the average temperature increases by one degree Celsius, the atmosphere can contain about 7% more moisture. This can lead to more raindrops and heavier rain, sometimes over short periods of time and in small areas. Scientists evaluate whether extreme weather events can be attributed to climate change by considering natural and human causes.

In the case of heavy rains in Dubai, the United Arab Emirates (UAE) and Oman in April 2024, it is difficult to accurately conclude the role of climate change. That's because heavy rain in this area is very rare, so scientists have very few historical examples to compare. However, the severity of these types of events has increased by 10 - 40% and climate change is the most likely explanation, according to World Weather Attribution (WWA).

The rain turned Dubai streets into rivers in early April. (Photo: NBC).

The same month, serious floods occurred in many places in East Africa. It is too early to conclude how climate change contributed to that event. But heavy rains in the same area in October and November 2023 were made worse by the combination of climate change and a natural weather phenomenon called the "Indian Ocean Dipole", according to WWA. In September 2023, northern Libya experienced deadly floods. Heavy rains are 50 times more likely due to climate change, and years of political instability have hampered efforts to prepare for such an event.

Globally, heavy rainfall events have become more frequent and intense in most land areas due to human activity, according to the United Nations Intergovernmental Panel on Climate Change (IPCC). This pattern will continue as the Earth warms.

2. Hot weather

Even small increases in average temperatures make a big difference in extreme heat. In early April 2024, the temperature in Mali reached 48.5 degrees Celsius during a heat wave in the Sahel region of Africa, associated with increased hospitalizations and deaths. Heat of this magnitude could not occur without human-caused climate change.

In the UK, temperatures reached 40 degrees Celsius for the first time in history in July 2022, causing widespread disruption across the country. The heat also lasts longer in many places, including the UK. That can happen because of a heat dome, a high-pressure area where hot air is forced down and trapped, causing temperatures to spike over a wide area.

One theory is that higher temperatures in the Arctic, which warms nearly four times faster than the global average, cause strong winds called jet streams to slow down, leading to the possibility of a heat dome. increase.

3. Drought

Linking climate change to individual droughts is quite difficult. Water availability depends on many factors other than temperature and rainfall, with natural weather systems also playing an important part. That was the case with the drought in southern Africa in early 2024. But heat from climate change could worsen the drought by drying out the soil, leading to rapid warming of the air above. and the heat becomes more intense.

During hot weather, demand for water increases, especially from farmers, placing an additional burden on water supplies. In many parts of East Africa, the rainy season was absent from 2020 to 2022 as the region experienced its worst drought in 40 years, leaving 1.2 million people in Somalia homeless. Climate change makes this type of drought at least 100 times more likely, according to WWA. Human-caused warming is also the main reason behind the most severe drought in the Amazon rainforest in half a century, occurring in the second half of 2023.

4. Forest fires

Fires occur naturally in many places around the world. It is difficult to know whether climate change is making wildfires worse because many other factors also contribute, such as land use changes. But climate change creates the weather conditions needed for fires to spread further, according to the IPCC. Prolonged extreme heat absorbs a lot of moisture from the soil and trees. Dry conditions provide fuel for fires to spread at incredible speeds, especially when winds are strong. Canada experiences its worst wildfire season in history in 2023. Climate change also doubles the likelihood of wildfire conditions in eastern Canada in May and June 2023.

Rising temperatures could increase the likelihood of lightning in northern forests, triggering fires. According to the United Nations Environment Program (UNEP), extreme fires will be more common and intense in the future globally due to the combined effects of land use change and climate change, with the number increase by 50% by 2100.