FACTBOX-U.N. panel issues stark climate change warning

(Reuters) - The U.N. Intergovernmental Panel on Climate Change (IPCC), the top world authority on global warming, issued a report on Friday based on the findings of 2,500 scientists.

More than 100 countries agreed on the following:

PROBLEMS SO FAR

-- Since the mid-20th century, rising temperatures are changing the face of the globe, mostly due to human production of greenhouse gases.

-- Researchers examined areas such as when trees sprout, compiled 29,000 sets of data and found that 90 percent of them pointed to global warming.

-- They say, with "medium confidence", that there have been more heat-related deaths in Europe, more infectious diseases and more pollen allergies because of global warming.

FUTURE FLOODS, DROUGHTS

-- Dry areas will get drier. In some countries, crop yields could drop by 50 percent by 2020.

-- The effect on agriculture will be uneven, with production increasing modestly in some places as it falls in others. As temperatures rise, the effects will change.