MANILA, Aug. 19 -- Climate change will slash up to 9 percent off the South Asian economy every year by 2100 if the world continues on its current "fossil-fuel intensive path," the Asian Development Bank (ADB) said Tuesday.

In a groundbreaking report titled "Assessing the Costs of Climate Change and Adaptation in South Asia," the Manila-based lender said its forecast assumes a 4.6 degree Celsius rise in global temperatures.

Given the uncertainties of climate change, ADB said there is a "slight chance" that annual losses will rise to as high as 24 percent by 2100.

"South Asia's economy is under serious threat and the lives and livelihoods of millions of South Asians inhabiting the region's many mountains, deltas, and atolls are on a knife edge," ADB Vice- President Bindu Lohani said in a statement.

The report noted that the Maldives and Nepal would be the hardest hit, losing up to 12.6 percent and 9.9 percent of their economies, respectively, every year, by 2100. Meanwhile, Bangladesh would lose 9.4 percent, India 8.7 percent, Bhutan 6.6 percent, and Sri Lanka 6.5 percent.

If the global community does not tackle the problem head on, ADB said almost all areas of South Asia will suffer due to the rise in temperature. For one, annual rice production will drop by as much as 23 percent in Bangladesh, India, and Sri Lanka by 2080.

Also, a 1-meter rise in sea levels would affect 95 million people and another 100 million when there are storm surges. Changes in rainfall pattern will make it harder to meet energy and water needs in the region and bring increased cases of dengue and diarrhea.

ADB said a concerted action to reduce dependence on fossil fuel and slow the rise in global temperatures would cut the projected financial and human toll of climate change on South Asian nations.

The report noted that if the rise in global temperatures is kept below 2 degrees Celsius under the so-called Copenhagen-Cancun agreement, then South Asia's economy would only be reduced by 1.3 percent annually by 2050 and 2.5 percent by 2100.