The latest United Nations assessment of climate science warns about dangers for the planet unless governments and industries do more to reduce emissions from burning carbon-based fuels such as oil and coal. A committee of international specialists also says it’s virtually certain that human activity is the main cause of global warming.

“Human influence on the climate system is clear.” according to a 36-page report summary issued for world leaders last week in Stockholm, the capital of Sweden. It tries to dispel doubts about the impact of emissions from factories, vehicles and other sources. The full 900-page study comes out this week.

“Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century,” the summary adds.

The findings come from the Intergovernmental Panel on Climate Change, a worldwide committee of hundreds of scientists that issues major reports every five or six years to give governments the latest knowledge on climate change. The 2013 report predicts a strong likelihood (more than a 90-percent probability) that sea levels will rise at a faster rate in coming decades than they have from 1971 until now, due to melting polar ice. The UN-sponsored group also forecasts: “It is very likely that heat waves will occur with a higher frequency and duration” in coming years and decades.

UN panel member says: “Climate change is the greatest challenge of our time. It threatens our planet, our only home.” -- Thomas Stocker, co-chairman of the Intergovernmental Panel on Climate Change

Journalist says: ”It will always be up to societies, balancing a host of factors, to figure out how to respond. The science is only one factor. But it has provided a sound foundation, and takes away the excuse of ignorance.” – Andrew Revkin, New York Times environmental reporter and blogger

Chinese scientist says: "As the ocean warms, and glaciers and ice sheets reduce, global mean sea level will continue to rise, but at a faster rate than we have experienced over the past 40 years." -- Qin Dahe, member of UN group