What happens if the world warms up by four degrees by the end of this century?
Warming on that scale will lead to food shortages, rising sea levels, cyclones and drought, according to a new report from the World Bank. And the world's poorest countries will be hit hardest.
This isn't the first study of its kind. Back in 2009, for example, the Intergovernmental Panel on Climate Change found that 3 billion people will have to choose between going hungry and moving their families to milder climates because of climate change.
But it's a little surprising to see the World Bank weigh in so forcefully on climate change.
The World Bank provides loans to developing countries, with the official goal of reducing poverty - meaning the organization is focused mainly on finance rather than climate science.
And in 2010, the Bank approved a $3.75 billion loan to develop a coal-fired power plant in South Africa, even though the U.S., Netherlands and Britain all raised environmental concerns.
But Jim Yong Kim, the head of the World Bank since July 1 of this year and the first-ever scientist to lead the organization, says he's determined to make a focus on climate change a bigger part of the Bank's approach to development.
"We will never end poverty if we don't tackle climate change. It is one of the single biggest challenges to social justice today," he told reporters on Friday.
And in his foreword, he writes, "It is my hope that this report shocks us into action. Even for those of us already committed to fighting climate change, I hope it causes us to work with much more urgency."
According to the report, which is called 'Turn Down the Heat,' extreme weather will become the "new normal" around the world unless global emissions are reduced, and rising sea levels will lead to the flooding of cities in places like Vietnam and Bangladesh.
Extreme heat waves would devastate a lot of the planet's land, while scarce water and falling crop yields would make hunger and poverty more widespread.
"If you look at all these things together, like organs cooperating in a human body, you can think about acceleration of this dilemma," said John Schellnhuber, director of the Potsdam Institute for Climate Impact Research, which along with Climate Analytics prepared the report for the World Bank.
"The picture reads that this is not where we want the world to go," he said.
Global development group Oxfam has responded to the report.
"There really is no alternative to urgent action given the devastating consequences of climate change," Oxfam said in a statement. "Now the question for the World Bank is how it will ensure that all of its investments respond to the imperatives of the report."
The report was released a week before the UN's COP18 Climate Change conference kicks off in Doha, where the Parties to the Kyoto Protocol will meet to discuss the future of that agreement.
Kyoto is the only legally binding effort to reduce emissions around the world, and it's set to expire at the end of 2012.
Al-Jazeera put together this infographic explaining where different countries stand on Kyoto. Canada withdrew from our commitment to the Protocol in 2011 (click on the graphic for a larger size).