Droughts, explained

Unlike weather events such as hurricanes and storms, droughts are usually hard to predict and to identify their start and end. In a warming and changing climate experiencing record temperatures, we can see more frequent and intense droughts across the globe. 2023 is “virtually certain” to be the warmest year in 125,000 years, according to European Union scientists. We’re already seeing and living its consequences.

A drought is defined depending on the average amount of precipitation that usually falls in a particular area and is caused by below-normal levels of precipitation in a region. Besides rainfall, some other indicators can be temperature, streamflow, ground and reservoir water levels, soil moisture and snowpack. Its start can be gradual and subtle, making it difficult to pinpoint. The same is true for its end. A single storm might provide temporary relief but not necessarily bring regular rainfall and water levels back to normal. The duration of droughts varies widely, from weeks to years.

In 2022, the UK recorded the driest summer in nearly 30 years. Eastern England was the most affected area by both record-breaking heat and drought. The region saw just over 76% of its annual rainfall. According to Defra, parts of East Anglia, Devon and Cornwall remained in drought for a year-long period since August 2022. The dry weather in May and June this year also put stress on Cumbria, Lancashire, and the West Midlands, as they entered prolonged dry weather status.

While droughts are natural phenomena and part of the weather cycle, global warming might play its part in contributing to their frequency and severity. Water tends to evaporate quicker at higher temperatures, reducing surface water and drying out soils and vegetation. A warmer climate also has the potential to worsen mild or moderate drought conditions, reduce snowfall, and shift air and ocean currents, changing weather patterns. Droughts are among the costliest weather events and have a potentially far-reaching effect.

Water supplies are the first to be affected in dry periods. Household use of water for routine activities such as drinking, cooking, cleaning, and watering plants can be limited – last year we saw a hosepipe ban across England. Water bills can also increase. Agriculture is another heavily impacted sector as lack of water affects livestock and crops, leading to food shortages and high prices.

Reduced flows in rivers and waterways also lead to poor water quality as it increases the concentration of pollutants, impacting both people and wildlife.

Droughts can also diminish a river’s ability to dilute pollutants as well as increase the risk of low oxygen levels. Low dissolved oxygen levels are devastating for fish which need dissolved oxygen in the water to survive. Sewage pollution in water can also drive up nutrient levels in water, which can result in producing algal blooms. The growing algae suck all the oxygen out of the water and can kill the wildlife within it.

Transportation, both on water and land – due to extreme heat – and energy grids become under stress as well. Some other devastating impacts for people can be unemployment, migration, and social unrest. Environmentally speaking, droughts harm vegetation, damage habitats, increase wildfire risks, and cause loss of biodiversity, and soil desertification.

Having said this, there are simple measures we can take to do our part and prepare for dry periods. A conservation mindset is extremely important to deal with extreme weather conditions. Mindful water consumption, repairing leaky taps, and installing green roofs and permeable pavements are actions we can take in our household. At Thames21, we implement bigger-scale nature-based solutions such as constructing wetlands, reconnecting rivers and floodplains, and restoring riverbanks in our projects to build ecosystem resilience. While these aren’t the perfect solution, they can help mitigate drought impacts.

If you feel like you want to do more for the environment, volunteer with us! There are plenty of opportunities to make a positive impact in your local area.