As temperatures rise and weather patterns shift, droughts are becoming more frequent and intense. But what is the relationship between climate change and the regularity of droughts? In this exploration, we delve into the science behind this complex and pressing issue, uncovering the ways in which a changing climate is worsening the drought conditions across the globe. From the impact on agriculture to the strain on water resources, it’s time to understand the connection and work towards finding solutions. Join us as we examine the relationship between climate change and the regularity of droughts.

The Short Answer

Climate change does not create droughts – those have always happened – but it makes them more likely to occur, more severe when they do, and quicker to arrive. The clearest link is not rainfall but temperature: a warmer atmosphere pulls more water out of soil, plants and reservoirs, so the same shortfall in rain produces a worse drought than it would have decades ago. Rainfall patterns are shifting too, and the share of precipitation falling as snow is dropping, which matters enormously to regions that live off meltwater.

What cannot be said is that any single drought was caused by climate change. Droughts have natural causes that still operate, and the honest statement for an individual event comes from attribution studies, which estimate how much more likely or how much more intense warming made it. Those studies now routinely find a measurable human contribution.

How Warming Makes Droughts Worse

Higher evaporative demand

Warmer air holds roughly 7% more moisture for every degree Celsius of warming, and it draws that moisture from wherever it can – soil, crops, lakes and rivers. This is why a drought can deepen in a year with normal rainfall, and it is the mechanism scientists are most confident about.

Less water stored as snow

In mountain regions, winter snowpack is a reservoir that releases water slowly through spring and summer. As more winter precipitation falls as rain instead, and what does fall as snow melts earlier, that release happens at the wrong time of year – so summer shortages worsen even where annual totals are unchanged.

Shifting rainfall patterns

Dry subtropical belts are expected to get drier and some wet regions wetter, and rainfall is becoming more concentrated into heavy events with longer dry spells between them. Rain that arrives in a few intense bursts runs off rather than soaking in, so it refills soil moisture less effectively than the same total spread over weeks.

Heat and drought arriving together

Dry soil cannot cool itself by evaporation, so it heats the air above it, which dries the soil further. This feedback is why heatwaves and droughts increasingly occur as a single compound event, and why they produce wildfire seasons and crop failures that neither would cause alone.

The Four Types of Drought

Much of the confusion in this debate comes from the word covering four different things, which do not begin or end at the same time:

• Meteorological drought: a sustained shortfall in rainfall against the local average. This is the one that starts first.
• Agricultural drought: too little moisture in the soil for crops and pasture at the point in the growing season when they need it. Warming pushes this one even when rainfall is normal.
• Hydrological drought: depleted rivers, reservoirs, lakes and groundwater. It lags the rainfall deficit by months and outlasts it, which is why reservoirs stay low after the rain returns.
• Socioeconomic drought: the point at which the shortage exceeds what people, farms, industry and power generation can absorb. This is where the damage figures come from.

A fifth term now in common use is flash drought – an unusually rapid onset, over weeks rather than seasons, driven by extreme heat and high evaporative demand rather than a long rainfall deficit. It is the type most directly attributable to warming, and the hardest to prepare for.

What Does The Data Show?

According to a Pew Research Centre Survey, drought is the one disaster that people worry most about out of all the dangerous climate change impacts. Due to climate change and global warming, droughts seem to be getting drier and longer in recent years. In 2012, the Western and Central United States was struck especially hard by droughts, forcing 81 percent of the country to live in extremely dry conditions. The disaster caused around $30 billion in damages and put the safety and health of numerous citizens at risk.

The COP15 recently released a report- “Drought in Numbers” – to the United Nations Convention to Combat Desertification. The report warned of the increasing frequency and intensity of droughts worldwide. India is one of the most severely affected drought countries: the country has even been featured in the Global Drought Vulnerability Index. Nearly two-thirds of India suffered droughts between 2020- 2022.

For Americans, droughts have become a frequent natural disaster. Droughts ranging from moderate to extreme conditions that covered the country in 2012 still continue today. Summer 2021 in America recorded the lowest water level at Lake Mead. Human-induced climate change contributes the most toward drought. Is there a relationship between climate change and the regularity of droughts?

Human activities lead to greenhouse gas emissions that trap heat in the atmosphere, causing heat waves and droughts. Rising temperatures increase the rate of evaporation, reducing surface water and drying out soil and vegetation. The condition makes periods with low precipitation driers than they would be in cooler conditions. The Southwestern United States is witnessing a decrease in annual precipitation since the beginning of the 20th century.

Rising temperatures also cause less precipitation to fall as snow, especially in the Northern Hemisphere, including regions like the Sierra Nevada of California. Decreasing snowpack is a serious issue, even if the total precipitation per year remains the same. Several water management systems and particular ecosystems depend on the melting of spring snowpacks. As snow acts as a reflective surface, the decrease in snow area will increase surface temperatures, aggravating drought conditions.

Source

So Is Climate Change Causing More Droughts?

According to certain climate models, warmer temperatures increase precipitation variability. Thus, there will be more periods of extreme precipitation and drought. The situation will lead to a higher risk of water shortage during droughts and increased flooding and dam failures during severe precipitation.

Most researchers and scientists see a relationship between climate change and the regularity of droughts. However, it does not always mean that one caused the other. Droughts are variable: they occur every few years or every year. But as increasing droughts correspond with climate change trends, more experts are correlating it with the same.

What Attribution Studies Can and Cannot Tell You

The careful answer to “did climate change cause this drought” is a probability, not a yes or no. Attribution research compares the observed event against model simulations of a world without human emissions, and reports how much more likely or how much more intense warming made it.

The long drought in the western United States through the 2000s and 2010s is the best-studied case: researchers have attributed a substantial share of its severity – roughly 40% of the soil-moisture deficit, in one widely cited 2022 analysis – to human-caused warming, with the remainder down to natural variability that would have produced a drought anyway, just a milder one. That is the shape of the finding to expect. Not “climate change did this”, but “this was a natural drought made considerably worse”.

Two honest caveats belong with it. Confidence varies by region: it is high for drying in the Mediterranean, south-western North America and parts of southern Africa and Australia, and lower where the rainfall record is short or the natural swings are large. And trends in meteorological drought are harder to detect than trends in agricultural drought, because rainfall is noisy while evaporative demand rises steadily with temperature. The evidence for drought getting worse is strongest exactly where the mechanism is temperature.

What Reduces the Damage

Drought risk is the product of the hazard and the exposure to it, and the second half is the part that can be changed quickly:

• Measure and meter water use, including groundwater, which is usually the least monitored and the first thing drawn down in a shortage.
• Fix the losses. Distribution leakage is often a larger volume than any saving available from restricting household use.
• Match crops and irrigation to the water that actually exists, rather than to a long-term average that is shifting.
• Protect soil organic matter. Soil that holds more water turns a rainfall deficit into a smaller agricultural drought.
• Plan for the hydrological lag. Reservoir and groundwater recovery takes far longer than the rain deficit, so restrictions should not be lifted when the rain returns.
• Cut emissions. Everything above limits the damage; only this limits how much worse the hazard becomes.