— VIOLENCE: For the first time, the panel is emphasizing the nuanced link between conflict and warming temperatures. Participating scientists say warming won't cause wars, but it will add a destabilizing factor that will make existing threats worse.
— FOOD: Global food prices will rise between 3 and 84 percent by 2050 because of warmer temperatures and changes in rain patterns. Hotspots of hunger may emerge in cities.
— WATER: About one-third of the world's population will see groundwater supplies drop by more than 10 percent by 2080, when compared with 1980 levels. For every degree of warming, more of the world will have significantly less water available.
— HEALTH: Major increases in health problems are likely, with more illnesses and injury from heat waves and fires and more food and water-borne diseases. But the report also notes that warming's effects on health is relatively small compared with other problems, like poverty.
— WEALTH: Many of the poor will get poorer. Economic growth and poverty reduction will slow down. If temperatures rise high enough, the world's overall income may start to go down, by as much as 2 percent, but that's difficult to forecast.
According to the report, risks from warming-related extreme weather, now at a moderate level, are likely to get worse with just a bit more warming. While it doesn't say climate change caused the events, the report cites droughts in northern Mexico and the south-central United States, and hurricanes such as 2012's Sandy, as illustrations of how vulnerable people are to weather extremes. It does say the deadly European heat wave in 2003 was made more likely because of global warming.
Texas Tech University climate scientist Katharine Hayhoe, who was not part of this report team, says the important nuance is how climate change interacts with other human problems: "It's interacting and exacerbating problems we already have today."
University of Colorado science policy professor Roger Pielke Jr., a past critic of the panel's impact reports, said after reading the draft summary, "it's a lot of important work ... They made vast improvements to the quality of their assessments."
Another critic, University of Alabama Huntsville professor John Christy, accepts man-made global warming but thinks its risks are overblown when compared with something like poverty. Climate change is not among the developing world's main problems, he says.
But other scientists say Christy is misguided. Earlier this month, the world's largest scientific organization, the American Association for the Advancement of Science, published a new fact sheet on global warming.
It said: "Climate change is already happening. More heat waves, greater sea level rise and other changes with consequences for human health, natural ecosystems and agriculture are already occurring in the United States and worldwide. These problems are very likely to become worse over the next 10 to 20 years and beyond."
Texas Tech's Hayhoe says scientists in the past may have created the impression that the main reason to care about climate change was its impact on the environment.
"We care about it because it's going to affect nearly every aspect of human life on this planet," she says.
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