Scientists and officials meeting in Japan say the document is the comprehensive assessment to date of the impacts of climate change on the world.
Members of the UN's climate panel say it provides overwhelming evidence of the scale of these effects.
Natural systems now bear the brunt, but a growing impact on humans is feared.
Our health, homes, food and safety are all likely to be threatened by rising temperatures, the summary says.
The report was agreed after almost a week of intense discussions here in Yokohama.
This is the second of a series from the Intergovernmental Panel on Climate Change (IPCC) due out this year that outlines the causes, effects and solutions to global warming.
This latest Summary for Policymakers document highlights the fact that the amount of scientific evidence on the impacts of warming has almost doubled since the last report in 2007.
Be it the melting of glaciers or warming of permafrost, the summary highlights the fact that on all continents and across the oceans, changes in the climate have caused impacts on natural and human systems in recent decades.