Arctic sea ice may vanish in summers this century even if governments achieve a core target for limiting global warming set by almost 200 nations in 2015, scientists said on Monday. …Under the 2015 Paris Agreement, governments set a goal of limiting the rise in average world temperatures to well below 2 degrees Celsius (3.6 Fahrenheit) above pre-industrial times, with an aspiration of just 1.5C (2.7F).
“The 2 degrees Celsius target may be insufficient to prevent an ice-free Arctic,” James Screen and Daniel Williamson of Exeter University in Britain wrote in the journal Nature Climate Change after a statistical review of ice projections.
A 2C rise would still mean a 39 percent risk that ice will disappear in the Arctic Ocean in summers, they said. Ice was virtually certain to survive, however, with just 1.5C of warming.And they said they estimated a 73 percent probability that the ice would disappear in summer unless governments make deeper cuts in emissions than their existing plans. They estimated temperatures will rise 3C (5.4F) on current trends….
New research describes how scientists have used the world’s largest array of seismic sensors to map a deep-Earth area of melting carbon covering 1.8 million square kilometers. Situated under the Western US, 350km beneath Earth’s surface, the discovered melting region challenges accepted understanding of how much carbon Earth contains — much more than previously understood.
….He continued, “Under the western US is a huge underground partially-molten reservoir of liquid carbonate. It is a result of one of the tectonic plates of the Pacific Ocean forced underneath the western USA, undergoing partial melting thanks to gasses like CO2 and H2O contained in the minerals dissolved in it.”
….As a result of this study, scientists now understand the amount of CO2 in Earth’s upper mantle may be up to 100 trillion metric tons. In comparison, the US Environmental Protection Agency estimates the global carbon emission in 2011 was nearly 10 billion metric tons — a tiny amount in comparison. The deep carbon reservoir discovered by Dr. Hier-Majumder will eventually make its way to the surface through volcanic eruptions, and contribute to climate change albeit very slowly.
“We might not think of the deep structure of Earth as linked to climate change above us, but this discovery not only has implications for subterranean mapping but also for our future atmosphere,” concluded Dr Hier-Majumder, “For example, releasing only 1% of this CO2 into the atmosphere will be the equivalent of burning 2.3 trillion barrels of oil. The existence of such deep reservoirs show how important is the role of deep Earth in the global carbon cycle…
Saswata Hier-Majumder, Benoit Tauzin. Pervasive upper mantle melting beneath the western US. Earth and Planetary Science Letters, 2017; 463: 25 DOI: 10.1016/j.epsl.2016.12.041
The future of humanity depends on math. And the numbers in a new study released Thursday are the most ominous yet.
Those numbers spell out, in simple arithmetic, how much of the fossil fuel in the world’s existing coal mines and oil wells we can burn if we want to prevent global warming from cooking the planet. In other words, if our goal is to keep the Earth’s temperature from rising more than two degrees Celsius—the upper limit identified by the nations of the world—how much more new digging and drilling can we do?
Here’s the answer: zero.
That’s right: If we’re serious about preventing catastrophic warming, the new study shows, we can’t dig any new coal mines, drill any new fields, build any more pipelines. Not a single one. We’re done expanding the fossil fuel frontier. Our only hope is a swift, managed decline in the production of all carbon-based energy from the fields we’ve already put in production….
…Scientists published a projection suggesting that for the third straight year, global carbon dioxide emissions did not increase much in 2016. The news comes from the Global Carbon Project, a group of scientists who measure how much carbon dioxide humans emit each year, as well as how much is subsequently absorbed by plants, land surfaces and oceans. The difference between the two determines the amount of carbon dioxide that remains in the atmosphere and drives global warming.
… this flattening occurred despite steady global economic growth above 3 percent, which has typically been coupled with higher emissions. And now, the group reports, 2016 appears to be similar to 2014 and 2015, based on early projections. It will be about a 0.2 percent increase above the emissions levels of 2015, the group calculates, or barely a rise at all….
China saw carbon dioxide emissions decrease by 0.7 percent in 2015 and is forecast to see an additional 0.5 percent decline in 2016. U.S. emissions are falling even faster. They declined by 2.6 percent in 2015 and are expected to fall an additional 1.7 percent this year…By comparison, in 2015 there was strong 5.2 percent emissions growth in India.
…slightly more than 36 billion tons of carbon dioxide are expected to have been emitted in 2016 from fossil fuel use and industrial activity. And after the oceans and the land take away their part, the rest of that carbon will stay there for a very long time, steadily warming the planet.
(That 36 billion tons does not include emissions of other greenhouse gases, such as methane, or the releases of additional carbon dioxide from deforestation and other nonindustrial causes. Including these gases and sources only increases our impact on the planet further.)…
…if global warming is ever to stop — and if we’re ever to cool the planet back down again — eventually emissions have to go to zero. Thirty-six billion tons is very far, indeed, from that. In fact, it’s looking increasingly likely that we may have to find some way to make emissions go negative (pulling more from the air than we put in) in the second half of this century.
The new research also suggests that, starting in 2017, the world will have only 800 billion tons, or gigatons, of carbon dioxide left to emit if it wants to preserve a two-thirds chance of preventing the planet from warming more than 2 degrees Celsius above preindustrial levels. This is the remaining global carbon “budget.” Based on emissions of 36 billion tons per year, we would bust the budget in 22 years….
…A new Yale-led study in the journal Nature finds that warming will drive the loss of at least 55 trillion kilograms of carbon from the soil by mid-century, or about 17% more than the projected emissions due to human-related activities during that period. That would be roughly the equivalent of adding to the planet another industrialized country the size of the United States.
Critically, the researchers found that carbon losses will be greatest in the world’s colder places, at high latitudes, locations that had largely been missing from previous research. In those regions, massive stocks of carbon have built up over thousands of years and slow microbial activity has kept them relatively secure.
Most of the previous research had been conducted in the world’s temperate regions, where there were smaller carbon stocks….
…The study predicts that for one degree of warming, about 30 petagrams of soil carbon will be released into the atmosphere, or about twice as much as is emitted annually due to human-related activities …This is particularly concerning, Crowther said, because previous climate studies predicted that the planet is likely to warm by 2 degrees Celsius by mid-century….
…The study considered only soil carbon losses in response to warming. There are several other biological processes—such as accelerated plant growth as a result of carbon dioxide increases—that could dampen or enhance the effect of this soil carbon feedback. Understanding these interacting processes at a global scale is critical to understanding climate change, the researchers said. “Getting a handle on these kinds of feedbacks is essential if we’re going to make meaningful projections about future climate conditions…
T. W. Crowther et al, Quantifying global soil carbon losses in response to warming, Nature (2016). DOI: 10.1038/nature20150
third-largest country for emissions, after the U.S. and China, to have done so
ratified countries total ~ 41% of global emissions; need to get to 55% for agreement to go into effect
remaining countries that emit more than Brazil, but have not yet ratified, are Russia (7.5 percent of emissions), India (4.1 percent), Japan (3.79 percent), and Germany (2.56). If all four of those countries also ratified this year, the agreement would easily enter into force.
RIO DE JANEIRO–Brazil, the country that’s home to the largest tropical rainforest on Earth, ratified the Paris climate agreement Monday — making it the third-largest country for emissions, after the U.S. and China, to have done so… Brazil’s ratification is significant because in order for the climate agreement to enter into force, 55 separate countries, accounting for 55 percent of global emissions, must sign and then ratify or otherwise approve it. Currently, according to the World Resources Institute, 27 countries have done so, representing 39.08 percent of those emissions (this total does not include Brazil).
However, the majority of those are small countries that don’t contribute much global carbon pollution (though the total also includes a few moderate sized countries like Norway and Peru). And then there are the U.S. and China, which just joined the agreement and account for a whopping 38 percent. Brazil, however, accounts for a very significant 2.48 percent of global emissions — making it the globe’s 7th highest emitter, and also a rather unique one in that so many of its emissions are due to deforestation of the Amazon, rather than the burning of fossil fuels.
…The country has reduced deforestation by 80 percent since 2004 — but significant portions of the vast Amazon rain forest are disappearing every year, and after a steady decline in deforestation rates from 2005 onwards, deforestation rose in both 2013 and 2015….The only remaining countries that emit more than Brazil, but have not yet ratified, are Russia (7.5 percent of emissions), India (4.1 percent), Japan (3.79 percent), and Germany (2.56). If all four of those countries also ratified this year, the agreement would easily enter into force. But other countries could also contribute to tipping the world into an officially active Paris regime, including Canada (1.95 percent), South Korea (1.85 percent), Mexico (1.7 percent), the U.K. (1.55 percent), Indonesia (1.49 percent), South Africa (1.46 percent) and Australia (1.46 percent).
Ban Ki-moon, secretary general of the United Nations, has called world leaders to the U.N. headquarters on the 21st of this month for a ratification ceremony for the Paris agreement. Some 175 have already signed, and along with the recent move by the U.S. and China, Brazil’s move just considerably increased the likelihood that there will be something to celebrate.
Staff writer Phillips contributed to this report from Rio de Janeiro; Chris Mooney from Washington.