Uxbridge — Extreme heat, flooding and water and food shortages will rock South Asia and Africa by 2030 and render large sections of cities inhabitable, if the world continues to burn huge amounts of coal, oil and gas, the World Bank is warning.
"Turn Down the Heat: Climate Extremes, Regional Impacts and the Case for Resilience", a new report commissioned by the World Bank and released Wednesday, analysed the expected effects on South Asia and Africa if global temperatures increase by two and four degrees Celsius.
The report showed that a global temperature rise of two degrees Celsius will have a wide range of dangerous effects, including a loss of 40 to 80 percent of cropland in Africa and rising sea levels that will destroy significant parts of many coastal cities in South Asia.
"If the world warms by two degrees Celsius - warming which may be reached in 20 to 30 years - that will cause widespread food shortages, unprecedented heat waves, and more intense cyclones," said World Bank President Jim Yong Kim.
He pointed out that such change could "greatly harm the lives and the hopes of individuals and families who have had little hand in raising the earth's temperature".
The burning of carbon-based fuels has increased the amount of carbon dioxide (CO2) in the atmosphere by 40 percent. CO2 and water vapour in the atmosphere are crucial in retaining some of the sun's heat energy; without them, the earth's atmosphere would be more like the moon's: 100 degrees Celsius in the daytime and -150 degrees at night.
Adding 40 percent more CO2, however, has increased the amount of heat energy the Earth absorbs, with more than 93 percent of it warming the oceans.
One of the shocking findings in the new study is the enormous impact a two-degree rise will have on the urban poor, said Rachel Kyte, the vice president for sustainable development at the World Bank.
Urbanisation is increasing rapidly, especially in the developing world, with many more people living in slums and informal settlements, Kyte told IPS from London.
As climate change disrupts rainfall patterns and generates more extreme weather in the coming decades, leading to poor crop yields, rural populations will flood cities. Escalating numbers of urban poor will suffer, with temperatures magnified by the "heat island effect" of the constructed urban environments.
Safe drinking water will also be harder to find, especially after floods, contributing to greater water-borne diseases such as cholera and diarrhoea.
Coastal regions like Bangladesh and India's two largest coastal cities, Kolkata and Mumbai, will face extreme river floods, more intense tropical cyclones, rising sea levels and very high temperatures.
"Huge numbers of urban poor will be exposed in many coastal cities," Kyte said.
Meanwhile, a sea level rise of 30 centimetres, possible by 2040, will result in massive flooding in cities and inundate low-lying cropland with saltwater, which is corrosive to crops. Vietnam's Mekong Delta, a global rice producer, is particularly vulnerable to sea level rise, and a 30-centimetre rise there could result in the loss of about 11 percent of crop production, the report found.
"We face a huge challenge over the next 20 years to... redesign our cities to protect them from climate change," Kyte predicted, even as cities already face a huge infrastructure investment gap.
One trillion dollars a year needed to be invested every year by 2020 by some estimates, Kyte said, adding that "to build climate resilience into cities will take another 300 to 500 million dollars a year".
A lack of water will be a problem in other regions. The projected loss of snowmelt from the Himalayas will reduce the flow of water into the Indus, Ganges and Brahmaputra river basins, which altogether threaten to leave hundreds of millions of people without enough water, food or access to reliable energy, the report said.
In Sub-Saharan Africa, by the decades of 2030 or 2040, drought mixed with destructive flooding will contribute to farmers' losing 40 to 80 percent of cropland used for growing maize, millet and sorghum.
And while carbon emissions have already increased oceans' acidity by 30 percent, by 2040, oceans will be too acidic for many coral reefs to survive. The death of coral reefs results in major loss of fish habitats as well as protection against storms.
"That will have significant consequences for ocean fish catches, which are already in decline today," said Bill Hare of Climate Analytics and who was the lead author of the study.
The report is a science-based guide for the World Bank and governments for what these regions will face over the next 20 to 30 years, said Hare.
"Much of this can be avoided, and it will cost far less with urgent action to reduce carbon emissions," Hare told IPS.
In a speech at Berlin's Brandenburg Gate Wednesday, U.S. President Barack Obama called climate change the "global threat of our time" and promised the United States would do far more to reduce emissions. A detailed announcement is expected next week.
Last week, the United States and China agreed to reduce phase out HFCs, a greenhouse gas used in air conditioners. China has also created a series of carbon trading regions to cut emissions.
"These are small positive signs that need to pickup momentum," Hare said.