The World Bank cautions that extreme heat waves fuelled by a 4-degree Celsius hike in temperature by century’s end are among the potential ill effects of failing to act on climate change.
The temperature increase could trigger “a cascade of cataclysmic changes that include extreme heat waves, declining global food stocks and a sea-level rise affecting hundreds of millions of people,” concludes a scientific report commissioned by the World Bank and released Sunday.
Turn Down the Heat, authored by the Potsdam Institute for Climate Impact Research and Climate Analytics (PIK), states the 4°C scenarios are potentially devastating. These include unprecedented heat waves in many regions, especially in the tropics; substantially exacerbated water scarcity in many regions; increased intensity of tropical cyclones; and many dry regions becoming dryer, wet regions wetter.
Extreme heat waves, that without global warming would be expected to occur once in several hundred years, will be experienced during almost all summer months in many regions, notes a statement from The World Bank. Increases of 6°C or more in average monthly summer temperatures would be expected in the Mediterranean, North Africa, Middle East and parts of the United States.
Agriculture, water resources, human health, biodiversity and ecosystem services are likely to be severely impacted, leading to large-scale displacement of populations and consequences for human security and economic and trade systems, the statement adds.
Current greenhouse gas emissions pledges will not reduce the temperature. “If we venture far beyond the 2-degrees guardrail, towards the 4-degrees line, the risk of crossing tipping points rises sharply,” PIK director John Schellnhuber explains in the statement. “The only way to avoid this is to break the business-as-usual pattern of production and consumption.”
With sustained policy action, warming can still be held below 2°C. Even the 2°C increase, however, brings some serious damages and risks to the environment and human populations, the statement adds.
The global mean temperature has continued to increase and is now about 0.8°C above pre-industrial levels. Many climate change impacts have already started to emerge, and the shift from 0.8°C to 2.0°C warming or beyond will pose much larger challenges.
“We need a global response equal to the scale of the climate problem, a response that puts us on a new path of climate smart development and shared prosperity. But time is very short,” Jim Yong Kim, president of The World Bank, notes in the statement.
Among other things, initiatives could include putting the more than US$1 trillion of fossil fuel and other harmful subsidies to better use; expanding both public and private expenditures on green infrastructure able to withstand extreme weather and urban public transport systems designed to minimize carbon emission and maximize access to jobs and services; and increasing energy efficiency (especially in buildings) and the share of renewable power produced.
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