Science, Tech & Health / Earth, Environment & Sustainability | February 11, 2016 GRAPHIC: The projected melting of the Greenland and Antarctic ice sheets throughout future millennia produce an average sea-level rise illustrated on the left. In the center, the impact of global deformation – prompted by the conversion of ice to seawater – adds to rising sea levels. At right, both long-term projections combine to show projected sea level rise around the globe in 10,000 years. (Courtesy of Nature Climate Change)
Thursday, February 18, 2016
To view the full Nature Climate Change report “Consequences of 21st Century Policy for Multi-Millennial Climate and Sea-Level Change,” visit: http://dx.doi.org/10.1038/nclimate2923
The damaging climate consequences of carbon emissions will grow and persist for millennia without a dramatic new global energy strategy, according to a new set of research-based climate change scenarios developed by an international team of scientists. Rising global temperatures, ice field and glacial melting and rising sea levels are among the climatic changes that could ultimately lead to the submergence of coastal areas that are home to 1.3 billion people today, according to the report, published online by the journal Nature Climate Change. The findings, the authors write, hold implications for policy makers because the projections reveal the intractability of a climate change across millennia. This long view, they note, should add urgency to efforts to significantly curb carbon emissions within the next few decades, not gradually across the remainder of the 21st century. “This long-term view shows that the next few decades offer a brief window of opportunity to minimize large-scale and potentially catastrophic climate change that will extend longer than the entire history of human civilization thus far,” the team concluded in its report “Consequences of 21st Century Policy for Multi-Millennial Climate and Sea-Level Change.” The new projections are based on leading research into contemporary and historical climate data, but also new scientific reconstructions of the only comparable period in human history: the last Ice Age.
“What our analysis shows is that this era of global warming will be as big as the end of the Ice Age. And what we are seeing is a massive departure from the environmental stability civilization has enjoyed during the last 10,000 years of its development.”
— BC paleo-climatologist Jeremy Shakun.
“This is the most comprehensive look at global climate in the past, present and future,” said Boston College paleo-climatologist Jeremy Shakun, a co-author of the report. “What our analysis shows is that this era of global warming will be as big as the end of the Ice Age. And what we are seeing is a massive departure from the environmental stability civilization has enjoyed during the last 10,000 years of its development.” The international team of co-authors, led by Peter Clark of Oregon State University, generated new scenarios for temperature rise, glacial melting, sea-level rise and coastal flooding based on state-of-the-art climate and ice sheet models. Under the most conservative scenario, the researchers used a projected global output of 1,280 billion tons of carbon across the next few centuries, far below estimated reserves of at least 9,500 billion tons. The projected consequences at this level of carbon emissions include:
- Global average temperature increase will exceed the recognized “guardrail” limit of 2 degrees Celsius.
- Melting of glaciers and the massive ice sheets of Greenland and Antarctica will combine for a rise in sea levels of 25 meters, or about 80 feet.
- Coastal submersion could displace as many as 1.3 billion people worldwide, a number that now accounts for approximately 19 percent of the world’s population.
As many as 25 “megacities” around the world could see rising oceans force at least 50 percent of their populations from their homes and businesses….