A new World Bank report says global warming will have dire consequences for countries in the Middle East and North Africa.
The study was presented at the United Nations climate negotiations in Qatar.
It says that average temperatures in Arab countries are likely to rise 3 degrees Celsius by 2050.
The report warns that rising temperatures will lead to hotter and drier conditions, which could devastate agriculture and tourism.
On December 4, UN Secretary-General Ban Ki-moon urged national delegations meeting in Qatar to try to agree on a new treaty to cut greenhouse-gas emissions linked to climate change.
The Doha talks on an extension of the Kyoto Protocol climate pact are due to end on December 7.
Nearly two weeks of talks have so far failed to produce significant progress.
In his address to delegates, Ban said a thaw in Arctic sea ice to record lows, “superstorms,” and rising sea levels were all indicators of a crisis.
He said signs of climate change were everywhere, noting droughts “from the United States to India, from Ukraine to Brazil.”
"Danger signs are all around," Ban said. "One-third of the world's population lives in countries with moderate to high water stress. Land degradation affects 1.5 billion people. Ice caps are showing unprecedented melting, permafrost is thawing, sea levels are rising. The abnormal is now the new normal."
The UN chief said no one on Earth will be immune from climate change.
"It is an existential challenge for the whole human race, our way of life, our plans for the future," he said. "We must take ownership. We collectively are the problem, then we should have the solutions."
Ban said superstorm Sandy, which hit the Caribbean and the East Coast of the United States one month ago, causing deaths and widespread destruction, should be a wake-up call that it’s past time for action.
A minority of scientists continue to question whether the global warming and weather events of recent decades are due to human activities, such as the burning of fossil fuels, which create carbon emissions.
Delegates say the failure so far to agree on an extension of Kyoto is hampering efforts to make progress toward a new treaty that would commit nations to firm cuts in emissions beginning in 2020. This new treaty is meant to be agreed upon by 2015.
Failure to extend the Kyoto pact, which expires at the end of this year, would leave the world without a binding United Nations framework for cutting emissions.
Wealthier countries and developing countries are still deeply divided on how much emissions should be cut in which countries, and how much richer countries should provide in aid to poorer countries to fund emissions reductions.
Kyoto, agreed on in 1992, required industrialized countries to cut their greenhouse-gas emissions by an average of 5.2 percent below 1990 levels between 2008 and 2012.
Russia, Japan, and Canada have announced they are pulling out of Kyoto, saying it is no longer relevant because developing countries such as China and India refuse to accept targets for imposing emissions limits.
The United States, the second-biggest emitter of greenhouse gases after China, never ratified Kyoto, also citing the pact's failure to address pollution from states like China and India.
The last attempt to negotiate a global deal to extend Kyoto, in 2009 in Copenhagen, failed to result in agreement.
With reporting from Reuters and AP