An increase in heat waves is almost certain, while heavier rainfall, more floods, stronger cyclones, landslides and more intense droughts are likely across the globe this century as the Earth’s climate warms, U.N. scientists said on Friday.
The U.N. Intergovernmental Panel on Climate Change (IPCC) urged countries to come up with disaster management plans to adapt to the growing risk of extreme weather events linked to human-induced climate change, in a report released in Uganda on Friday.
The report gives differing probabilities for extreme weather events based on future greenhouse gas emissions scenarios, but the thrust is that extreme weather is likely to increase.
“It is virtually certain that increases in the frequency and magnitude of warm daily temperature extremes … will occur in the 21st century on the global scale,” the IPCC report said.
“It is very likely that the length, frequency and/or intensity of warm spells, or heat waves, will increase,” it added.
“A 1-in-20 year hottest day is likely to become a 1-in-2 year event by the end of the 21st century in most regions,” under one emissions scenario.
An exception is in very high latitudes, it said. Heat waves would likely get hotter by “1 degrees C to 3 degrees C by mid-21st century and by about 2 degrees C to 5 degrees C by late-21st century, depending on region and emissions scenario.”
Delegates from nearly 200 countries will meet in South Africa from November 28 for climate talks with the most likely outcome modest steps toward a broader deal to cut greenhouse gas emissions to fight climate change.
Carbon emissions up
The United Nations, the International Energy Agency and others say global pledges to curb emissions of CO2 and other greenhouse gases are not enough to prevent the planet heating up beyond 2 degrees Celsius, a threshold scientists say risks an unstable climate in which weather extremes become more common and food production more difficult.
Global carbon emissions rose by a record amount last year, rebounding on the heels of recession.
“It is likely that the frequency of heavy precipitation or the proportion of heavy rainfall from heavy falls will increase in the 21st century over many areas of the globe,” especially in “high latitudes and tropical regions.”
For the IPCC, “likely” means a two-thirds chance or more.
It said there was “medium confidence” that this would lead to “increases in local flooding in some regions”, but that this could not be determined for river floods, whose causes are complicated.
The report said tropical cyclones were likely to become less frequent or stay the same, but the ones that do form are expected to be nastier.
“Heavy rainfalls associated with tropical cyclones are likely to increase with continued warming. Average tropical cyclone maximum wind speed is likely,” the report said.
That, coupled with rising sea levels were a concern for small island states, the report said.
Droughts, perhaps the biggest worry for a world with a surging population to feed, were also expected to worsen.
The global population reached 7 billion last month and is expected to reach 9 billion by 2050, according to U.N. figures.
“There is medium confidence that droughts will intensify in the 21st century … due to reduced precipitation and/or increased evapotranspiration,” including in “southern Europe and the Mediterranean region, central Europe, central North America, Central America and Mexico, northeast Brazil and southern Africa.”
There is a high chance that landslides would be triggered by shrinking glaciers and permafrost linked to climate change, it said.
