Ecology, Climate Change and Related News

Conservation Science for a Healthy Planet

Tag Archive: 2C

  1. Young People’s Burden: Requirement of Negative CO2 Emissions

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    James Hansen, et al. Young People’s Burden: Requirement of Negative CO2 Emissions. Earth System Dynamic doi:10.5194/esd-2016-42

    Abstract. The rapid rise of global temperature that began about 1975 continues at a mean rate of about 0.18 °C/decade, with the current annual temperature exceeding +1.25 °C relative to 1880–1920. Global temperature has just reached a level similar to the mean level in the prior interglacial (Eemian) period, when sea level was several meters higher than today, and, if it long remains at this level, slow amplifying feedbacks will lead to greater climate change and consequences.

    The growth rate of climate forcing due to human-caused greenhouse gases (GHGs) increased over 20 % in the past decade mainly due to resurging growth of atmospheric CH4, thus making it increasingly difficult to achieve targets such as limiting global warming to 1.5 °C or reducing atmospheric CO2 below 350 ppm.

    Such targets now require “negative emissions”, i.e., extraction of CO2 from the atmosphere. If rapid phasedown of fossil fuel emissions begins soon, most of the necessary CO2 extraction can take place via improved agricultural and forestry practices, including reforestation and steps to improve soil fertility and increase its carbon content. In this case, the magnitude and duration of global temperature excursion above the natural range of the current interglacial (Holocene) could be limited and irreversible climate impacts could be minimized.

    In contrast, continued high fossil fuel emissions by the current generation would place a burden on young people to undertake massive technological CO2 extraction, if they are to limit climate change. Proposed methods of extraction such as bioenergy with carbon capture and storage (BECCS) or air capture of CO2 imply minimal estimated costs of 104–570 trillion dollars this century, with large risks and uncertain feasibility.

    Continued high fossil fuel emissions unarguably sentences young people to either a massive, possibly implausible cleanup or growing deleterious climate impacts or both, scenarios that should provide both incentive and obligation for governments to alter energy policies without further delay.

  2. Negative Emissions Key to Meeting 2°C Threshold

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    Bobby Magill July 12th, 2016 Climate Central

    Humans will have to not only stop emitting greenhouse gases by 2085, but also develop technology that will result in negative emissions — the removal of 15 billion tons of carbon dioxide from the atmosphere each year by the end of the century —  in order to prevent global warming from exceeding 2°C (3.6°F), according to a new study.

    Human greenhouse gas emissions, including methane and carbon dioxide, have already warmed the globe more than 1°C (1.8°F) compared to pre-industrial levels. The Paris Climate Agreement negotiated last year seeks to cap warming to below 2°C, while at the same time pursuing an even more ambitious goal of limiting warming to 1.5°C.

    But according to a new National Center for Atmospheric Research study, just cutting emissions under the Paris agreement may not be enough to keep global warming from blasting past 2°C, said Benjamin Sanderson, the study’s lead author.

    Meeting the Paris agreement as written will require a long-term commitment to negative emissions in the last two decades of the century, he said…

    Sanderson et al. What would it take to achieve the Paris temperature targets? Geophysical Research Letters Full publication history DOI: 10.1002/2016GL069563

  3. Coastal cities at risk from rapid sea-level rise with warming above two degree

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    Coastal cities at risk from rapid sea-level rise with warming above two degree

    Posted: 08 Nov 2016 04:31 AM PST

    The first predications of coastal sea level with warming of two degrees by 2040 show an average rate of increase three times higher than the 20th century rate of sea level rise, report scientists…According to this research, by 2040 with 2 degrees centigrade warming, more than 90% of coastal areas will experience sea level rise exceeding the global estimate of 20cm, with up to 40cm expected along the Atlantic coast of North America and Norway due to ocean dynamics. Furthermore, the impact of this sea level rise will be more pronounced in locations, such as Jakarta, where there is subsidence of the land.

    Dr Svetlana Jevrejeva from the NOC, who is the lead author on this paper, said “Coastal cities and vulnerable tropical coastal ecosystems will have very little time to adapt to the fast sea level rise these predictions show, in scenarios with global warming above two degree.

    A worst case scenario considered involving 5 degrees warming shows that up to 80% of global coastlines could experience changes in sea level of over 1.8 meters by the end of 21st century. This might never happen, but could not be ruled out due to large uncertainties in the contribution of Greenland and Antarctic ice sheets in these sea level rise predications. As a result, millions of people living by the coast could be displaced and the beaches that attract tourists could be destroyed, particularly in low lying coastal cities in South East Asia and in the USA, such as Miami.”…

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    Svetlana Jevrejeva, Luke P. Jackson, Riccardo E. M. Riva, Aslak Grinsted, John C. Moore. Coastal sea level rise with warming above 2 °C. Proceedings of the National Academy of Sciences, 2016; 201605312 DOI: 10.1073/pnas.1605312113

  4. A World at War—under attack from climate change—only hope to mobilize like WWII

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    We’re under attack from climate change—and our only hope is to mobilize like we did in WWII.

    https://newrepublic.com/article/135684/declare-war-climate-change-mobilize-wwii

    By Bill McKibben August 15, 2016 New Republic

    In the North this summer, a devastating offensive is underway. Enemy forces have seized huge swaths of territory; with each passing week, another 22,000 square miles of Arctic ice disappears. Experts dispatched to the battlefield in July saw little cause for hope, especially since this siege is one of the oldest fronts in the war. “In 30 years, the area has shrunk approximately by half,” said a scientist who examined the onslaught. “There doesn’t seem anything able to stop this.”

    In the Pacific this spring, the enemy staged a daring breakout across thousands of miles of ocean, waging a full-scale assault on the region’s coral reefs. In a matter of months, long stretches of formations like the Great Barrier Reef—dating back past the start of human civilization and visible from space—were reduced to white bone-yards.

    Day after day, week after week, saboteurs behind our lines are unleashing a series of brilliant and overwhelming attacks. In the past few months alone, our foes have used a firestorm to force the total evacuation of a city of 90,000 in Canada, drought to ravage crops to the point where southern Africans are literally eating their seed corn, and floods to threaten the priceless repository of art in the Louvre. The enemy is even deploying biological weapons to spread psychological terror: The Zika virus, loaded like a bomb into a growing army of mosquitoes, has shrunk the heads of newborn babies across an entire continent; panicked health ministers in seven countries are now urging women not to get pregnant. And as in all conflicts, millions of refugees are fleeing the horrors of war, their numbers swelling daily as they’re forced to abandon their homes to escape famine and desolation and disease.

    World War III is well and truly underway. And we are losing.

    ….Even if every nation in the world complies with the Paris Agreement, the world will heat up by as much as 3.5 degrees Celsius by 2100—not the 1.5 to 2 degrees promised in the pact’s preamble.

    And it may be too late already to meet that stated target: We actually flirted with that 1.5 degree line at the height of the El Niño warming in February, a mere 60 days after the world’s governments solemnly pledged their best efforts to slow global warming.

    …What would it mean to mobilize for World War III on the same scale as we did for the last world war?…

    ….In the past year, the Stanford team has offered similar plans for 139 nations around the world. The research delves deep into the specifics of converting to clean energy…

    But would the Stanford plan be enough to slow global warming? Yes, says Jacobson: If we move quickly enough to meet the goal of 80 percent clean power by 2030, then the world’s carbon dioxide levels would fall below the relative safety of 350 parts per million by the end of the century. The planet would stop heating up, or at least the pace of that heating would slow substantially. That’s as close to winning this war as we could plausibly get. We’d endure lots of damage in the meantime, but not the civilization-scale destruction we currently face. (Even if all of the world’s nations meet the pledges they made in the Paris accord, carbon dioxide is currently on a path to hit 500 or 600 parts per million by century’s end—a path if not to hell, then to someplace with a similar setting on the thermostat.

    …it’s important to remember that a truly global mobilization to defeat climate change wouldn’t wreck our economy or throw coal miners out of work. Quite the contrary: Gearing up to stop global warming would provide a host of social and economic benefits, just as World War II did. It would save lives…