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Hot decade is behind us
The global terrestrial temperature data for the analysis of NASA experts reached the conclusion that the current observations about 130 years since the last decade was the warmest period on Earth. The U.S. aerospace agency further concluded that, during this time of the year 2009 was the second warmest year. Indeed, only last year, only a few degrees Celsius during the time the temperature was milder csúcstartónak counting after the year 2005. James Hansen, NASA Goddard Institute for Space Research (GISS), director, global hőmérsékletváltozásért the oceans warm and cold légáramlatainak responsible for the alternation. "When I looked in the past five or ten years, the variation of air currents, it was concluded that global warming will continue" - said the expert, who was one of the scientists, who have two decades ago drew attention to the dangers of global warming.
The La Nina weather phenomenon known as two years ago, so cooled the tropical Pacific areas that in 2008 it was the coldest year of the decade. NASA experts were clear in temperature over the past decades, although in the 1940s and 1970s, some equilibrium between observed. The data suggest that over the past thirty years, roughly 0.2 degrees Celsius increase in temperature of the decade. The average global temperature of 0.8 degrees has increased since 1880. "That number should keep in mind" - says Gavin Schmidt, of the Institute éghajlatkutatója.
2009, even if the second warmest year acquired title to North America last year, most of the affected part of an unusually cold December, and the Arctic is much lighter than normal air currents come from. NASA has analyzed data on thousands of worldwide meteorological station, the sea surface temperature observation satellites, and the Arctic kutatóállomásokról arrived.
The climate summit in Copenhagen last month completed the participants agreed that it is necessary to prevent a further rise in global average temperature, and thereby eliminated its most devastating effects. "We have a contradiction in the current climate changes and the results of popular beliefs in" - said Hansen. "Over the past decade, global warming does not stand still" - he added.
Mongol Invasion in 1200s Altered Carbon Dioxide Levels
Catastrophes and carbon
Pongratz and her colleagues used a detailed reconstruction of historical agriculture to model the effect of four major wars and plagues in the 800 to 1850 time period: the Mongol takeover of Asia (from about 1200 to 1380), the Black Death in Europe (1347 to 1400), the conquest of the Americas (1519 to 1700) and the fall of the Ming Dynasty in China (1600 to 1650).
All of these events led to death on a massive scale (the Black Death alone is thought to have killed 25 million people in Europe). But Mother Nature barely noticed, the researchers found. Only the Mongol invasion had a noticeable impact, decreasing global carbon dioxide by less than 0.1 part per million. This small amount required that the forests absorb about 700 million tons of carbon dioxide, which is the amount emitted annually by worldwide gasoline demand today. But it was still a very minor effect, Pongratz said.
"Since the pre-industrial era, we have increased atmospheric CO2 [or carbon dioxide] concentration by about 100 parts per million, so this is really a different dimension," she said.
Another factor was that while one part of the world burned, the rest planted. In the case of the conquest of the Americas in particular, Pongratz said, native people with a minimal agricultural footprint were dying, while deforestation continued across the globe.
The role of agriculture
Studies of Antarctic ice cores suggest that carbon dioxide dropped much more during these eras than the models by Pongratz and her team revealed. That may mean that natural factors, such as changes in solar radiation, played a larger role in atmospheric carbon dioxide than reforestation during this time, Pongratz said.
The global terrestrial temperature data for the analysis of NASA experts reached the conclusion that the current observations about 130 years since the last decade was the warmest period on Earth. The U.S. aerospace agency further concluded that, during this time of the year 2009 was the second warmest year. Indeed, only last year, only a few degrees Celsius during the time the temperature was milder csúcstartónak counting after the year 2005. James Hansen, NASA Goddard Institute for Space Research (GISS), director, global hőmérsékletváltozásért the oceans warm and cold légáramlatainak responsible for the alternation. "When I looked in the past five or ten years, the variation of air currents, it was concluded that global warming will continue" - said the expert, who was one of the scientists, who have two decades ago drew attention to the dangers of global warming.
The La Nina weather phenomenon known as two years ago, so cooled the tropical Pacific areas that in 2008 it was the coldest year of the decade. NASA experts were clear in temperature over the past decades, although in the 1940s and 1970s, some equilibrium between observed. The data suggest that over the past thirty years, roughly 0.2 degrees Celsius increase in temperature of the decade. The average global temperature of 0.8 degrees has increased since 1880. "That number should keep in mind" - says Gavin Schmidt, of the Institute éghajlatkutatója.
2009, even if the second warmest year acquired title to North America last year, most of the affected part of an unusually cold December, and the Arctic is much lighter than normal air currents come from. NASA has analyzed data on thousands of worldwide meteorological station, the sea surface temperature observation satellites, and the Arctic kutatóállomásokról arrived.
The climate summit in Copenhagen last month completed the participants agreed that it is necessary to prevent a further rise in global average temperature, and thereby eliminated its most devastating effects. "We have a contradiction in the current climate changes and the results of popular beliefs in" - said Hansen. "Over the past decade, global warming does not stand still" - he added.
