Electronic Scientific Paper Archive
Dangerous Global Warming Closer Than You Think, Climate Scientists Say
Abrupt climate change is not only imminent, it's already here. The rapid dwindling of summer Arctic sea ice has outpaced all scientific projections, which will have impacts on everything from atmospheric circulation to global shipping. And plants, animals and other species are already struggling to keep up with rapid climate shifts, increasing the risk of mass extinction that would rival the end of the dinosaurs. So warns a new report from the U.S. National Research Council.
That's exactly why longtime climate scientist James Hansen and a panoply of scientists and economists are urging in another new paper that current efforts to restrain global warming are woefully inadequate. In particular, global negotiations to limit global warming to no more than 2 degrees Celsius risk "wrecking the planet," in the words of lead author Hansen, recently retired head of the Goddard Institute for Space Studies and a researcher at Columbia University's Earth Institute.
"We started this paper to provide a basis for legal actions against governments for not doing their jobs and protecting the rights of young people and future generations," Hansen said of the paper, entitled "Assessing 'Dangerous Climate Change.'" "We can't burn all these fossil fuels. There is no recognition of this in government policies."
The paper, published in PLOS ONE, lays out the case for why fossil fuel emissions to date are dangerous enough to permanently alter the planet's climate—raising CO2 concentrations in the atmosphere above 400 parts-per-million, or levels not seen in at least 3 million years. Global emissions of CO2 from burning fossil fuels—which set another new high in 2012, according to the Global Carbon Project—must decline to zero new pollution within the next few decades, according to the analysis. "Affordable, clean energy is probably the biggest requirement that the planet has," Hansen noted at a gathering of journalists at Columbia University to discuss the new analysis.
Given the size of the problem—the fossil fuels of coal, oil and natural gas still provide more than 80 percent of the world's energy—an "all of the above" clean energy effort will be required, according to Hansen and his co-authors. That includes geothermal, hydropower, nuclear, solar, wind and further development of technologies to capture CO2 from fossil fuel burning and permanently store it in some way. Increasing efficiency in the use of such energy as well as switching cars from running on gasoline to electricity will also be vital. "What's called normal is completely reckless," said co-author and economist Jeffrey Sachs of the Earth Institute, addressing the growth rates in fossil fuel pollution of roughly 3 percent per year, putting the world on a pathway to roughly 4 degrees C of warming by century's end. "To decarbonize the energy system very deeply would require a scale of effort unlike anything seen almost anywhere in the world."