Climate change drives disaster risk

Climate change can increase disaster risk in a variety of ways - by altering the frequency and intensity of hazard events, affecting vulnerability to hazards, and changing exposure patterns.

Disaster risk is magnified by climate change; it can increase the hazard while at the same time decreasing the resilience of households and communities.

Climate change refers to a change in the climate that persists for decades or longer, arising from either natural causes or human activity. Climate change is already modifying the frequency and intensity of many weather-related hazards as well as steadily increasing the vulnerability and eroding the resilience of exposed populations that depend arable land, access to water, and stable mean temperatures and rainfall. Risk to weather-related hazards is concentrated in low and middle-income countries. Although the precise impact of climate change is not certain, and it is important to be aware that not all areas will be impacted in the same way, projected impacts of climate change that will drive disaster risk include:

• Droughts: The number of people suffering extreme droughts across the world could double in less than 80 years, which has major implications for the livelihoods of the rural poor, and can also lead to increased migration streams. There will likely be a large reduction in natural land water storage in two-thirds of the world, especially in the Southern Hemisphere.
• Sea level rise: Coastal flooding events could threaten assets worth up to 20 % of the global GDP by 2100. The population of coastal areas has grown faster than the overall increase in global population. Global “hotsports” for flooding are projected to be in north western Europe and Asia.
• Infectious diseases: By 2050, mosquitoes that carry vectore-borne diseases like Malaria could reach an estimated 500 million people. Global warming has led to a loss in biodiversity, resulting in increased transmission and incidence of disease. Due to altered climate patterns, urbanization and deforestation bats and rodents, which are responsible for 60 percent of the diseases transmitted from animals to humans, have flourished.
• Wildfires: By 2030, fire season could be three months longer in areas already exposed to wildfires. In Western Australia, for example, this would add up to three months of days with high wildfire potential.
• Cyclones: Even though the attribution of tropical cyclones to climate change is difficult, a robust increase of the most devastating storms with climate change is evident. Under 2.5°C of global warming, the most devastating storms are projected to occur up to twice as often as today.

Changes in the geographic distribution of weather-related hazards, which may lead to new patterns of risk. An example on changes in geographic distribution of hazards: How changes in weather patterns could lead to more insect invasions.

Risk associated with weather-related hazards is disproportionately concentrated in developing countries and within these countries in poorer sectors of the population. Poverty and constrained access to productive assets mean that rural livelihoods that depend on agriculture and other natural resources are vulnerable to even slight variations in weather and seasonality.

IPCC, 2012

The impact of climate change in rural and urban areas is intimately linked. As the sustainability of rural livelihoods declines and disaster risk increases, it is possible that increased rural to urban migration may occur. Related to climate change, in rural areas more frequent and extreme droughts, as well as changes in mean temperature and precipitation levels will cause further stress to these already vulnerable livelihoods.

Illustration depicting an example of an impact chain that conceptualizes risks to farmers and the agricultural sector, retrieved from Technical guidance on comprehensive risk assessment and planning in the context of climate change, UNDRR (2022).