Drought and extreme events: the climate are scary. UN: “Act now. Delay means death”.
Human-induced climate change is causing dangerous and widespread disruptions in nature and affecting the lives of billions of people around the world, despite efforts to reduce risks.
Cities increasingly at risk. Heat waves, storms, droughts, and floods threaten people’s health, lives, and livelihoods, as well as critical infrastructure, including energy and transportation systems.
Drought and Desertification
These are the findings of the new IPCC report ‘Climate Change 2022: Impacts, Adaptation and Vulnerability’.
With global warming of +1.5 degrees, the world will face multiple unavoidable climate risks over the next two decades. Even temporarily exceeding this level of warming will cause further severe impacts, some of which will be irreversible ‘as natural and human systems are pushed beyond their ability to adapt’, causing ‘mass die-offs in species such as trees and corals’.
These extreme weather events have ‘cascading impacts that are increasingly difficult to manage’ and have ‘exposed millions of people to severe food and water insecurity, especially in Africa, Asia, Central and South America, the Small Islands and the Arctic’. This is the alarm raised by UN climate change scientists (IPCC).
Warming will reduce suitable habitats for current terrestrial and marine ecosystems and irreversibly change their composition, with effects whose severity increases above the 2 C global warming level.
Measures to adapt to the heat stress of the population and to contain the risks from heat waves require multiple interventions in buildings and urban spaces. Long-term analyses show significant increases in drought risk in all scenarios, with a particularly large increase in the Mediterranean area.
In Europe, aridity would affect an increasing proportion of the population: with warming of 3°C above pre-industrial levels, it is estimated that 170 million people would be affected by extreme drought. If warming is limited to 1.5°C, the population exposed to these conditions would fall to 120 million.
In southern Europe, the number of days with insufficient water resources (availability below demand) and droughts increases under all global warming scenarios. Under the 1.5°C and 2°C global temperature increase scenarios, water scarcity affects 18% and 54% of the population respectively. Similarly, soil dryness increases with global warming: in a 3°C temperature increase scenario soil dryness is 40% higher than in a 1.5°C temperature increase scenario.
The level of the sea in the Mediterranean increased by 1.4 mm per year during the 20th century. The increase accelerated at the end of the century and is expected to continue rising in the future at a rate similar to the global average, potentially reaching values close to one metre by 2100 in the event of a high level of emissions.
Sea-level rise, the study points out, is already having an impact on Mediterranean coasts and will increase the risks of coastal flooding, erosion and salinisation in the future. Narrow sandy coastlines that are of great value to coastal ecosystems and tourism are at risk of disappearing.
Adaptation includes engineering works (of various scales) and soft/ecosystems, as well as shoreline retreat. Engineering works, in spite of their efficiency, have negative effects on ecosystems, on the tourist attractiveness of coasts and on economic and financial costs, which make them advantageous only for densely populated areas. Soft/ecosystemic systems are limited by competition with other activities in land use. In many Mediterranean countries, planning does not appear to take into account the possibility of marked rises in sea level.
Cities and coastal settlements increasingly at risk by 2100 in the absence of significant adaptation and mitigation actions. The population at risk in cities and coastal settlements will increase by about 20 % at a global average sea level rise of 0.15 m above current levels; double at 0.75 m rise and triple at +1.4 m rise.