The effects of a warming planet are likely to be vast and varied — ranging from increased droughts and coastal flooding to reductions in snow and ice. But while most climate predictions look ahead to the potential risks 50 or 100 years from now, there are places around the globe that are already being impacted by global warming.
Satellite measurements have demonstrated that the waters of Australia's Great Barrier Reef have warmed by 0.36 degrees Fahrenheit (0.2 degrees Celsius) on average over the past 25 years. This warming has led to a decline in the amount of seafloor covered in thriving coral.
A 2012 study published in the journal Proceedings of the National Academy of Sciences found that half of the Great Barrier Reef was lost in the past 27 years.
Warming oceans, linked to rising emissions of carbon dioxide, increase the risk of coral bleaching — a phenomenon that disrupts the symbiotic relationship between corals and the organisms that live within their tissues and provide food the corals need to survive.
Higher-than-normal ocean temperatures cause corals to expel the tiny animals and algae that live inside them. This turns the corals white and places the reef-building animals — and the entire ecosystem — under stress.
Newtok, and many other villages in Alaska, are built atop permanently frozen soil, called permafrost. As ocean temperatures increase, Alaska's permafrost melts, causing the ground to erode and many of these remote, coastal towns to sink.
Newtok is located on the western coast of Alaska, on the edge of the rising Ninglick River. The flood-prone town already sits below sea level, and researchers have said the entire village could be underwater within a decade. [What 11 Billion People Mean for Climate Change]
Now, members of the community are hoping to relocate Newtok's 350 residents to higher ground, at a site roughly 9 miles (14 kilometers) away. But there are financial and political barriers. For instance, the U.S. Government Accountability Office estimates that moving the town of Newtok could cost up to $130 million.
The Indian metropolis of Mumbai is one of the places at risk of dangerous and costly floods due to climate change, according to a report released earlier this year by the World Bank. Economists at the World Bank examined 136 large coastal cities, and evaluated their coastal defenses and level of protection.
The report identified Mumbai as one of the coastal cities that face a high risk of devastating floods due to global warming. Researchers found the city's existing defenses against flooding and storm surges are only designed to withstand current conditions, not for the anticipated rise in sea levels that will make future floods more devastating.
While coastal defenses are a start, "if they are not upgraded regularly and proactively as risk increases with climate change and subsidence, defenses can magnify — not reduce — the vulnerability of some cities," study leader Stephane Hallegatte, an economist at the World Bank, said in a statement.
The Alps, one of the most famous mountain ranges in Europe, have long been a tourism hotspot, famous for their top-notch ski resorts and as a popular year-round destination for outdoors enthusiasts. But climatologists warn that global warming could spell trouble for the sprawling alpine region.
Since the late 19th century, temperatures in the Alps have been steadily rising, from an average yearly temperature of 49.3 degrees F (9.6 degrees C) in the late 1800s to today's average of 51.4 degrees F (10.8 degrees C), according to Gilles Brunot, a meteorologist based at the ski resort Chamonix-Mont-Blanc in southeastern France.
But concerns about global warming's effect on the Alps extend beyond the region's ski industry. About 40 percent of Europe's freshwater originates from the Alps, which stretch from Austria in the East to France in the West, dipping into parts of Italy and Monaco in the South. Climate change is threatening the area's water cycle, which includes patterns of precipitation, snow and glacier cover. [8 Ways Global Warming is Already Changing the World]
Farmers across China's Gansu Province, one of the country's driest regions, are already struggling to cope with the effects of climate change, as droughts and arid land contribute to the region's vast poverty. The United Nations says warming temperatures are shrinking glaciers in central Asia and the Himalayas, which typically replenish China's rivers.
China recently completed its first National Census of Water, and found that as many as 28,000 of the country's rivers have disappeared since the 1990s. The study did not identify reasons for the loss of the rivers, but the research showed an alarming trend of dwindling water resources throughout the country.
China currently has 2,100 cubic meters (74,000 cubic feet) of water resources per person — roughly 28 percent of the global average, according to Reuters. But as the country's population grows, these supplies could dry up sooner than expected.