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As levels of CO2 in the atmosphere rise, scientists are grappling with a mountain of data to form an accurate picture of the future. Scientists from the Geological Society of London now believe that most current climate models only look to the short term, and that long term analysis finds the Earth to be twice as sensitive to CO2 as previously thought.
Led by Dr. Colin Summerhayes, the team of researchers published their statement in an update to “Climate change: Evidence from the Geological Record” written in 2010. They looked at geological evidence from past studies that took into account the decay of ice sheets and the operation of the full carbon cycle. They also considered recent data that reveals how historic temperature increases rose in tandem with CO2 trapped in Antarctic ice cores.
According to patterns in past climate data, the Earth should be cooling for another 1,000 years due to movements in its orbit and axis. Yet, human activity has added so many greenhouse gasses to the atmosphere that the period between 1950 and 2000 is the warmest on record for the past 2,000 years. Currently, atmospheric carbon sits at just below 400ppm, a level last seen during the Pliocene between 5.3 and 2.6 million years ago. Then, global temperatures were 2-3°C higher, causing the melting of the Antarctic ice sheet and sea levels that were several meters higher.
If the Earth reaches 600ppm, humans can expect to witness conditions not seen in 24 million years, including more acidic and less oxygenated oceans, mass extinctions, and severe storms. If levels are not brought under control, the scientists assert that it could take the planet 1,000 years to reach equilibrium.
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