The Nobel Peace Prize-winning U.N. Intergovernmental Panel on Climate Change (IPCC) released on Friday the current version of its climate report predicting extreme weather events such as heat waves, heavy rains, and droughts.

The IPCC SREX Summary for Policymakers report -- calling upon governments and businesses to step up infrastructure modifications to control climate change -- may become new ammunition for U.S. Democrats and environmentalists in their ongoing battle against conservative Republicans and others who deny global warming is partially the result of human activity.

It is virtually certain that increases in the frequency and magnitude of warm daily temperature extremes and decreases in cold extremes will occur in the 21st century on the global scale, according to the IPCC report. It is very likely that the length, frequency and/or intensity of warm spells, or heat waves, will increase over most land areas.

In certain scenarios, the report noted a 1-in-20-year hottest day is likely to become a 1-in-2-year event by the end of the 21st century in most regions, except in the high latitudes of the Northern Hemisphere, where it is likely to become a 1-in-5-year event. It also pointed out, It is likely that the frequency of heavy precipitation or the proportion of total rainfall from heavy falls will increase in the 21st century over many areas of the globe.

Meanwhile, There is medium confidence that droughts will intensify in the 21st century in some seasons and areas, due to reduced precipitation and/or increased evapotranspiration, the report stated.

The report also indicated there is at least a two-thirds chance that humans can be held responsible for the planet's rising temperatures and other extreme weather events.

Environmentalists have pointed to a number of natural disasters that have plagued this year, causing damages of $1 billion or more, to reinforce their claims.

However, the IPCC has a history of being criticized, both about the specific content of its reports and about the methods undertaken to produce the reports. Some scientists have voiced their skepticism about humans being held responsible for climate change, which, they argue, has been a cyclic process at work even before mammals appeared on the face of the earth.