Dr. James Hansen: 1º C More and oceans will rise 8 meters

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“If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that [current levels] will have CO2 reduced to a maximum of 350 ppm. ”

Dr. James Hansen

Prevent the temperature from rising more than two degrees Celsius is not enough, concluded Dr. James Hansen, a climate expert and former NASA scientist change. As explained in their study published in the journal European Geoscience Union, two degrees over global warming could be catastrophic for humanity, because in just 50 years, the sea level will rise 3-8 meters.

The situation had already lived before. The evidence indicates that an increase in temperature of just 1 degree Celsius, came to raise sea level between 4 and 9 meters, which in turn led to extreme storms will form over a hundred thousand years ago.

Through the publication, Hansen and the 16 co-authors, have made an appeal to politicians, as in 2009, world leaders pledged under the Copenhagen Accord, not to let the temperature to rise more than two degrees . Which, apparently, is not enough.

“The message for policy makers is that we have a global crisis that requires international cooperation to reduce emissions quickly,” the authors explained in the Huffington Post.

To achieve these projections, the group of scientists took into account that the crusts of ice in Antarctica and Greenland are melting faster due to high concentrations of greenhouse gases are in the atmosphere. Which in turn causes the icy water reaches the oceans, change circulation patterns and, like a domino effect, end up getting new ice caps melt. A process that, in conclusion, makes the sea level rise faster than projected.

Hansen was director of the Institute of Space Studies of NASA until August 2013 and is now an assistant professor at the University of Columbia. However, it has been criticized by some of his colleagues and the Association of Scientific Press for its alarmist tone. In fact, Seth Borenstein, one of its members, said on Twitter that he would not cover their statements until the article was reviewed by experts. Process they must undergo all the research are published in scientific journals of disclosure and dissemination.

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* This report, once collated and confirmed by the scientific community, changes the picture of the situation on climate change and puts us in planetary emergency since we are close to reach 1 over global average temperature. Hence the need for extreme measures such as emergency and intensive Solidarity Fund 2% of world GDP and Eco Government Planetarium.

At the current rate of increase of carbon dioxide in the atmosphere, the planet probably experience varying degrees of increase in global temperature and large-scale changes such as loss of ice sheets that could bring an increase in sea level several meters this century. As he stated by James Hansen of NASA in a recent article.

The global average surface temperature of the Earth has risen 0.8 degrees Celsius since 1880, and is now increasing at a rate of about 0.1 degrees per decade.

In new research on the paleoclimate history of the Earth by the NASA Goddard Institute director James Hansen suggests a potential for rapid climate change during this century, including several meters sea level rise if climate change is not It is reduced.

Studying the climate of the Earth responded to past natural changes, Hansen investigated one of the key issues arising from climate change caused by man: What is the dangerous level of climate change? Some international leaders have suggested a goal of limiting to two degrees Celsius compared to pre-industrial times to avoid catastrophic change. But Hansen said at a news conference at a meeting at the American Geophysical Unidon in San Francisco on 8 December that a warming of two degrees could lead to drastic changes, such as a significant loss of ice in Greenland and in Antarctica.

Based on the analytical work temperature Hansen GISS, the average global surface temperature of the Earth has risen 0.8 ° C since 1880 and now is warming at a rate of more than 0.1 ° C per decade. This warming is largely driven by the increase in greenhouse gases, particularly carbon dioxide, emitted by burning fossil fuels in power plants, cars and industry. At the current rate of burning fossil fuels, the concentration of carbon dioxide in the atmosphere will have doubled compared to pre-industrial levels by mid-century. Doubling the level of carbon dioxide would cause eventual heating of various degrees, according to Hansen.

In recent research, Hansen and co-author Makiko Sato, also from GISS compared the climate of today, the Holocene, with a similar period of interglacial periods – periods when the polar ice caps exist but the world was dominated by glaciers.

Studying corals drilled ice sheets and deep ocean sediments, Hansen found that global mean temperatures during the Eemian, which began 130,000 years ago and lasted about 15,000 years, were less degree warmer than today.

If temperatures to rise 2 ° C over pre-industrial times, the average global temperature could far exceed that of the Eemian, when sea level was four to six meters higher than today, Hansen said.

“The paleoclimate record reveals a more sensitive than we thought, even from a few years ago climate. Limiting warming by two degrees caused man is not enough, “Hanen said:” It would be a recipe for disaster. ”

Hansen focused much of the work as the polar regions and in particular the ice sheets of Antarctica and Greenland react to a warmer world.

Two degrees Celsius of warming would make a planet Earth much warmer than during the Eemian, and bring it closer to the conditions of the Pliocene, when the sea level was about 25 meters higher than today, Hansen said. Using the climate history of Earth learn more about the level of sensitivity that governs the response to warming the planet today. Hansen said the paleoclimate record suggests that every degree Celsius global temperature rises could eventually assume rising 20 meters from sea level. However, the sea level increases due to loss of the ice would be expected to occur for centuries and remain large uncertainties in predicting how ice loss will arise.

Hansen notes that the disintegration of the ice will not be a linear process. This nonlinear deterioration that has already been seen in vulnerable places such as Pine Island Glacier in West Antarctica, where the rate of ice loss has continued accelerating during the past decade. Data from NASA’s Gravity Recovery and Climate Experiment Satellite (GRACE) is already consistent with the rate of mass loss of sea ice in Greenland and West Antarctica that doubles every ten years. GRACE is too short to confirm this with great certainty, however, the trend in the past few years does not rule, according to Hansen. This continued rate of ice loss could cause several meters of sea level rise by 2100.

Sediment cores from the ocean and ice in the polar regions indicate that temperatures at the poles during previous epochs – when sea level was several dozen meters taller is not too far from the Earth temperatures could reach this century if everything continues on the current path.

“We have a substantial cushion between today’s climate and dangerous warming,” Hansen says, “The Earth is about to experience a strong amplified feedback in response to further moderate global warming.”

Detailed considerations of a new warming target and how to get there than the object of this research, Hansen said. But this research is consistent with previous findings of Hansen in carbon dioxide need back from 390 parts per million in the atmosphere today to 350 million pairs to stabilize the long-term climate. As leaders continue to discuss a framework for reducing emissions, global carbon dioxide emissions have remained stable or have increased in recent years.

Hansen and others indicate that while the paleoclimate evidence paints a clear picture of how was the previous Earth’s climate, but using it to predict precisely how the climate might change a lot shorter time scales in response to human-induced, shows signs response, even in the chaos of “slow feedbacks” such as changes in ice sheets.

The human-caused emissions of carbon dioxide in the atmosphere also presents climatologists something they had never seen in 65 million years of record levels of carbon dioxide. A drastic rate increase which makes it difficult to predict how the Earth will respond quickly. In periods when carbon dioxide has increased due to natural causes, the rate of increase averaged 0.0001 parts per million per year – in other words, 100 parts per million every million years. The burning of fossil fuels is now causing the concentrations of carbon dioxide increase in two parts per million per year.

“Humans have exceeded the slow changes that occur in natural geologic time scales,” says Hansen. http://www.ecoportal.net

ARTICLE

The article focuses on the effects of 2 ° C warming Earth’s average. What seems almost inevitable, because we have already warmed 0,85ºC, there are nearly as many to come, because of the huge thermal inertia of the planet. Besides, we still emit heat-trapping gases: We’ve already passed the 400 ppm CO2 concentration in the atmosphere and each year we increase the concentration in other 3 ppm. At this rate, by 2030 we will have passed the 450 ppm that the UN, the IPCC and almost 100% of the international scientific community sets a limit to no more than 2 ° C …

Well, James Hansen concludes that, with 2 ° C of warming, these consequences are almost inevitable:

1. current sea level rise of about 3 meters to the end of the century (IPCC spoke of one meter. But the IPCC positions must agree with everyone, so that their conclusions are always conservative). It draws on the Eemian, about 100,000 years ago, when, with an average temperature just 1 ° C more than today, the sea level rose between 5 and 9 meters (16 to 30 feet)

2. Worried disruption of ocean currents by massive input of fresh water, both in the Gulf Stream and Antarctic currents by melting polar ice.

Well, three meters of sea level rise is enough to destroy and impossible to live in 15 of the 20 most populated macrocities land (including New York, Los Angeles, Tokyo, Mumbai, Buenos Aires, Miami, Houston, London, Cairo, Lagos, Shanghai, Hong Kong, Cadiz, Valencia, Barcelona, ​​Corunna, Santander, ….). Flooding the most productive deltas of wheat, corn and rice. Flooding entire countries (Netherlands, Bangladesh, the first). World agriculture would suffer unbearable losses for a population that will be between 9,000 and 11,000 million …

The social, migration, widespread proliferation of failed states can be devastating.

The paper is being reviewed by peers (peer-review process). At this stage, the scientific community reads and writes the article. The authors reply or correct. Until it reaches the final version. This time, they are doing online to arrive before the cop21.

This is one of the comments of one of the scientists who criticized Michael Oppenheimer of Princeton: “The article emphatically answers the question of when this will happen … which in my opinion, remains in very dark area. But given the uncertainty and high risk, the best humanity can do is lift off the accelerator “.

That is, “I may be wrong, they may not 3 meters and something may happen later, but will we be so foolish to the point of checking if he was right?”

Hansen is optimistic. He believes there is still time to avoid disaster. It intends to take immediate measures to eliminate the burning of fossil fuels and invest massively in “Negative emissions” (systems CO2 capture and storage, geological and biological), to reduce the concentration of CO2 to 350 ppm ….

See the complete study here.


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