IN SPACE - UNSPECIFIED: In this handout illustration made available on December 5, 2011 by NASA, a diagram compares our own solar system to Kepler-22, a star system containing the first 'habitable zone' planet discovered by NASA's Kepler mission. The habitable zone is the sweet spot around a star where temperatures are right for water to exist in its liquid form. Liquid water is essential for life on Earth. The diagram displays an artist's rendering of the planet comfortably orbiting within the habitable zone, similar to where Earth circles the sun. Kepler-22b has a yearly orbit of 289 days. The planet is the smallest known to orbit in the middle of the habitable zone of a sun-like star and is about 2.4 times the size of Earth. (Image credit: Getty Images via @daylife)
WASHINGTON, DC - APRIL 19: Cookies in the shape of lightning bolts, wind turbines and the sun were served during the Newsmaker Luncheon on renewable and alternative energy at the National Press Club April 19, 2011 in Washington, DC. BP Capital Management CEO T. Boone Pickens and fellow billionaire Turner Enterprises CEO Ted Turner addressed the luncheon and said they agree on most things, including global warming, the need to move away from a dependency on foreign oil and the need to end the wars in Iraq and Afghanistan. (Image credit: Getty Images via @daylife)
BEIJING, CHINA - MARCH 31: Badaling Great Wall principal venue beijng of the Earth Hour 2012 power switch off on March 31, 2012 in Beijing, China. About 124 Chinese cities joined a WWF worldwide initiative Earth Hour, to call on people to switch off unnecessary lights for one hour tonight, in support for energy-saving efforts and global warming prevention as a shared responsibility. (Image credit: Getty Images via @daylife)
Graph showing historic atmospheric CO2 concentrations (from Antarctic ice cores) and recent atmospheric CO2 concentrations (from Hawaii air) (Photo credit: Wikipedia)
Cumulative Vs Annual Emissions (2006) of carbon dioxide (Photo credit: CarbonQuilt)
HEFEI, CHINA - MARCH 26: (EDITORS NOTE: Image is a digital composite) This composite photograph shows Swan Lake before and during the Earth Hour 2011 power switch off on March 26, 2011 in Hefei, Anhui Province of China. About 86 Chinese cities joined a WWF worldwide initiative Earth Hour, to call on people to switch off unnecessary lights for one hour tonight, in support for energy-saving efforts and global warming prevention as a shared responsibility. (Image credit: Getty Images via @daylife)
CO2-src (Photo credit: Wikipedia)
Carbon Dioxide Sequestration (Photo credit: PNNL - Pacific Northwest National Laboratory)co2-forced climate thresholds during the Phanerozoic
A significant obstacle to testing the antiquity of the CO2-temperature link is generating accurate records of CO2 and temperature for times in Earth’s past that are tens
to hundreds-of-million years old.
I compare 490 published proxy records of CO2 spanning the Ordovician to Neogene
with records of global cool events to evaluate the strength of CO2-temperature coupling over the Phanerozoic (last 542 my). For periods
with sufficient CO2 coverage, all cool events are associated with CO2 levels below 1000 ppm. A CO2 threshold of below 500 ppm is
suggested for the initiation of widespread, continental glaciations, although this threshold was likely higher during the Paleozoic due to a lower solar luminosity* at that time.
Did Shakun et al really prove that co2 rises preceded late global warming
Right off the bat, a most surprising conclusion in this paper is that the authors claim that correlation proves cause. Simply showing that CO2 correlates with anything surely doesn’t prove that CO2 was the cause. It’s the same kind of mindset involved with the oft-heard claim that if we have had global warming while CO2 was rising that proves the cause was the rise in CO2. Heck, I had hair before CO2 began to rise, but I don’t blame that on CO2.