NAIROBI — The United Nations called Monday on rich nations to forge a “Global Green New Deal” that puts the environment, climate change, and poverty reduction at the heart of efforts to reboot the world economy.

Leaders from the Group of 20 nations, meeting in April, should commit at least 1 percent of gross domestic product over the next two years to slashing carbon emissions, the United Nations Environment Programme said in a report released at the opening of its world forum in Nairobi.

“Reviving the world economy is essential, but measures that focus solely on this objective will not achieve lasting success,” the UNEP cautioned, invoking the U.S. New Deal launched by Franklin Roosevelt in the 1930s.

“Unless new policy initiatives also address other global challenges — reducing carbon dependency, protecting ecosystems and water resources, alleviating poverty — their impact on averting future crises will be short-lived.”

The world’s most developed economies must take the lead by adopting national plans to slash their use of the fossil fuels — oil, gas and coal — that drive global warming, the report says.

Measures could include the elimination of fossil fuel subsidies worth hundreds of billions of dollars, and the development of carbon pricing, either through taxes or cap-and-trade schemes.

The G20’s rapidly emerging economies such as China, India, Brazil, South Africa, and Turkey “should aim, as far as possible” for the same one percent of GDP targets, the UNEP urged.

Poorer and developing nations cannot be expected to make the same carbon-cutting commitments, but should spend at least one percent of GDP on expanded access to clean water and sanitation for the poor, it said.

Twenty percent of people in the developing world lack sufficient clean water, and about half — some 2.6 billion — do not have basic sanitation.

In general, it is the world’s poor who have been hit hardest by rising food prices, and who will bear the brunt of climate change impacts including rising sea levels, expanding deserts, more violent storms and the spreading of disease.

Even before the current global economic crisis, it was estimated that, by 2015, there will be nearly one billion people living on less than one U.S. dollar a day, and almost 3 billion living on less than two.

The current recession is likely to increase those numbers significantly, noted the study’s author, American economist Edward Barbier from the University of Wyoming.

“The Global Green New Deal is not just about creating a greener world economy,” the report said.

“It is about ensuring that the correct mix of economic policies, investments and incentives reduce carbon dependency, protect ecosystems and alleviate poverty while fostering economic recovery and creating jobs.”

Returning the world economy to a “business-as-usual” scenario would set the planet on a collision course with social, economic and ecological disaster, the report argues.

Global energy demand is set to rise by 45 percent by 2030, according to the International Energy Agency.

Depending on fossil fuels to satisfy this appetite would likely double atmospheric greenhouse gas concentrations by century’s end, causing global temperatures to jump by six degrees Celsius (10.8 degrees Fahrenheit).

Such an increase would not only unleash terrible environmental consequences, but would also slash five-to-ten percent off the world economy’s GDP, according the Stern Review, an economic analysis of the impact of global warming.

A green New Deal would cost a fraction of that, and would have the added benefit of creating millions of jobs, the UNEP said.

The green economy investments, for example, in U.S. President Barack Obama’s nearly 800-billion dollar stimulus package total 100 billion dollars over the next two years — just over 0.7 percent of the U.S. GDP — and should create two million new jobs.