According to the World Meteorological Organisation, the occurrence of extreme weather is increasing in frequency and intensity worldwide, largely due to climate change. The scientific community agrees that as long as the emission of greenhouse gases continues, the situation will persist [1]. Here are four key mechanisms linking climate change to extreme weather events. [2]
1. Intensification and Prolonging of Heatwaves
Even a marginal rise in average global temperatures has profound impacts. This causes the daily temperature distribution to skew towards higher levels, rendering hot days more frequent and extreme. According to simulations, events like the heatwaves that affected southern Europe, the southern US, and Mexico in July 2023 would have been “virtually impossible” without human-caused climate change, as per the World Weather Attribution network (WWA) [3]. Should global temperatures reach 2C above pre-industrial levels, such events could occur every 2-5 years. In the UK, for instance, temperatures crossed the 40C threshold for the first time on record in July 2022, a phenomenon termed “extremely unlikely” without climate change by the WWA. [3]
2. Prolongation of Drought Conditions
While attributing individual drought events to climate change is challenging, it’s clear that more prolonged and intense heat waves exacerbate drought conditions by drying out soils [2]. Increased water consumption during these periods further strains resources. East Africa, for example, experienced five consecutive failed rainy seasons from 2020 to 2022, constituting the region’s worst drought in 40 years. Such droughts are now at least 100 times more likely due to climate change, as per the WWA. [3]
3. Amplification of Wildfire Risks
Although fires are a natural phenomenon in various ecosystems, climate change augments the conditions conducive to the spread of wildfires. The Intergovernmental Panel on Climate Change (IPCC) confirms that climate change is increasing the likelihood of suitable weather for wildfires [2]. Drier conditions resulting from intense and prolonged heat contribute to the fires’ rapid spread. Canada’s worst-ever wildfire season, with 176,000 sq km already burnt, was made more likely by climate change, according to the WWA. [3]
4. Increase in Extreme Precipitation
Each 1C increase in average temperature allows the atmosphere to hold approximately 7% more moisture, leading to heavier and more intense rainfall. Recent flooding in northern Libya, for example, was made up to 50 times more likely by human-caused climate change, according to the WWA. [3]
Sources
- WMO (2022). More bad news for the planet: greenhouse gas levels hit new highs. [online] public.wmo.int. Available at: https://public.wmo.int/en/media/press-release/more-bad-news-planet-greenhouse-gas-levels-hit-new-highs.
- Pinto, I., Vicente-Serrano ; Nathan, S., Gillett, P., Canada, Greve, P., Gudmundsson, L. and Li, C. (2021). Lofti Halimi (Algeria). José Manuel Guttiérez (Spain), [online] (Spain). doi:https://doi.org/10.1017/9781009157896.013.
- Anon, (n.d.). Extreme heat in North America, Europe and China in July 2023 made much more likely by climate change – World Weather Attribution. [online] Available at: https://www.worldweatherattribution.org/extreme-heat-in-north-america-europe-and-china-in-july-2023-made-much-more-likely-by-climate-change/#:~:text=In%20China%20it%20would%20have [Accessed 23 Oct. 2023].