If the world doesn't cut the levels of greenhouse gases in the atmosphere, the already noticeable harms of global warming could spiral "out of control", according to a 32-volume, 2,610-page report released by the Intergovernmental Panel on Climate Change.
'We're now in an era where climate change isn't some kind of future hypothetical,' said the overall lead author of the report, Chris Field of the Carnegie Institution for Science in California. 'We live in an area where impacts from climate change are already widespread and consequential.'Reuters
Recent disasters such as droughts in Australia and deadly flooding in Mozambique, Thailand and Pakistan show how vulnerable we are to extreme weather. The dangers are going to worsen as the climate changes even more, the report's authors said.
While global warming will hit everyone in some way, it will be worse for the people who can least afford it, the report says. It will increase the gaps between the rich and poor, healthy and sick, young and old, and men and women.
Scientists are seen during a study of Arctic sea ice in July 2011. There are warning signs that damage to coral reefs and Arctic Sea ice may be irreversibleReuters/NASA
Huge chunks of ice peel off from the Perito Moreno glacier in Argentina in an unexpected rupture during the southern hemisphere's winter months, in July 2008. Higher temperatures would cause glaciers in East Africa, the Alps, the Rockies and the Andes to retreat, leading to drinkable water shortages and a rise in sea levelsReuters
An aerial view of Male, the capital of the Maldives, taken on December 14, 2009. President Mohamed Nasheed said that two degrees Celsius warming would risk swamping the coral atolls and islets that form his countryReuters
A man in scuba diving gear wades through floodwaters in Saint Mark's Square in Venice on December 3, 2010. Rising sea levels could threaten the city's existenceReuters
Survivors take part in a religious procession in Tolosa on the eastern Philippine island of Leyte on November 18, 2013, a week after Super Typhoon Haiyan devastated the area. Deadly storms like Haiyan, Sandy and Nargis may not have been caused by warming, but their storm surges are augmented by ever rising seasAFP
Rain clouds gather over the city of Sao Paulo on May 4, 2009. The report suggests that electricity stations and other infrastructure could be wiped out by increasingly severe stormsReuters
Houses in Staines-Upon-Thames are surrounded by water on on February 16, 2014. The report suggests that British winters are likely to become milder and wette, while summers will be hotter and drierGetty
Residents use a donkey cart to transport their belongings out of the flooded Pangrio town in Pakistan's Sindh province on September 14, 2011. Unprecedented torrential monsoon rains caused flooding that killed more than 400 people and damaged 1.5 million homesReuters
The report echoes an earlier UN climate science panel that said if greenhouse gases continue to rise, the world is looking at about 3.5 or 4 degrees Celsius of warming by 2100. The difference, Princeton's Oppenheimer said, "is the difference between driving on an icy road at 30 mph versus 90 mph. It's risky at 30, but deadly at 90."
Global warming is triggered by heat-trapping gases, such as carbon dioxide, that stay in the atmosphere for a century. Much of the gases still in the air and trapping heat came from the United States and other industrial nations. China is now by far the number one carbon dioxide polluter, followed by the United States and India.
A traffic policeman signals to drivers Harbin, Heilongjiang province, on October 21, 2013, when pollution forced the closure of schools and highwaysReuters
Tourists walk on Moscow's Red Square in heavy smog caused by peat fires in nearby forests, on August 9, 2010 during Russia's worst heatwave in over a centuryReuters
An aerial view of the Yueyaquan Crescent Lake in Dunhuang, in China's northwestern Gansu province, surrounded by sand dunes a result of increasing desertificationGetty / Reuters
Workers harvest soybeans at a farm in western Brazil, on March 5, 2009. Climate change could mean a drastic reduction in crop yields, leading to food poverty and instabilityReuters
A Somali fisherman carries a swordfish from the port to the market in Mogadishu on February 11, 2014. Rising sea temperatures could lead to a mass migration of fish stocks, leading to critical food shortages in tropical regionsAFP
March 12, 2014: A small dam is seen in a dry paddock next to an area that has been affected by a recent fire on the outskirts of Melbourne. Australia endured its hottest year on record in 2013, with average temperatures 1.2 degree Celsius above the long-term average of 21.8 degrees, and breaking the previous record set in 2005Reuters
A mother holds her malnourished child at the Mirriah refugee camp in Niger on May 31, 2012. A coup in Mali forced more than 320,000 people from their homes, with 187,000 seeking refuge in neighbouring countries, including Niger -- already in the grips of a drought that put millions at risk of hungerAFP
Firefighters scurry down a blazing hillside to escape a sudden flare-up while tackling a huge wildfire in California. Fires are expected to become more regular and more severe as temperatures rise, drying out the vegetationReuters
Smoke from a bushfire billows over beach goers at Carlton, Tasmania, where temperatures reached record highs on January 4, 2013,Reuters