Malcolm Turnbull, 29 March, Lateline:

The IPCC report is based on peer-reviewed published science, everything in there is well known to us, we know that there is the possibility or the probability of a hotter and drier future in southern Australia.

I mean we know about this, this has been published, the CSIRO has been writing about this for years so I’m glad that you think it’s a revelation, I’m sorry to say that it isn’t, it isn’t, there’s nothing new in that.

Those comments came as a surprise to many viewers, given the Howard government’s general reluctance to admit the dangers of climate change. But it raises the question, how long have Howard and Turnbull been aware of the those dangers? Here’s how long:

1896: Swedish scientist Svante Arrhenius proposes a connection between atmospheric carbon dioxide levels and temperature. With American geologist Thomas Chamberlain, Arrhenius calculates that human activities, especially since the industrial revolution, are contributing to global warming.

1924: US chemist and demographer Alfred Lotka speculates that, based on coal use levels in 1920, atmospheric CO2 will double in 500 years.

1949: British scientist Guy S. Callendar posits a link between the estimated 10% increase of atmospheric CO2 between 1850 and 1940 with observations of climate warming in northern Europe and North America dating back to the 1880’s.

1954: Yale biologist G. Evelyn Hutchison suggests a link between deforestation and increased levels of atmospheric CO2.

1956: Physicist Gilbert N. Plass turns his mind to calculating the transmission of radiation through the atmosphere, further strengthening the likelihood that  higher atmospheric CO2 levels would trap radiation, thereby increasing temperatures.

1957: Roger Revelle and Hans Suess debunk the theory that oceanic absorption of CO2 will put a brake on global warming.

1958: Charles Keeling begins to measure precise rises in CO2 on a year-by-year basis. According to a biography found here, “The Keeling record of the increase in atmospheric carbon dioxide measured at Mauna Loa, Hawaii, and at other ‘pristine air’ locations, represents what many believe to be the most important time-series data set for the study of global change.”

1967: Princeton computer specialists release a report with “reasonably solid” estimates of “the global temperature change that was likely if the amount of CO2 in the atmosphere doubled.”

1979: The US National Academy of Science reports to president Jimmy Carter: “If carbon dioxide continues to increase, the study group finds no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible…A wait-and-see policy may mean waiting until it is too late.”

1985: the United Nations Environment Program (UNEP), the World Meteorological Organization (WMO), and the International Council of Scientific Unions reach agreement on the issue of climate change. The conference report warns “that some future warming appears inevitable due to past emissions regardless of future actions.”

1987: An ice core from a drilling team in Antarctica showsCO2 levels…got as low as 180 parts per million in the (earth’s) cold periods and reached 280 in the warm periods, never higher. But in the air above the ice, the level of the gas had reached 350 — far above anything seen in this geological era and still climbing.”

1988: The UN establishes the Intergovernmental Panel on Climate Change ahead of the 1992 Rio Earth Summit.

1990: The IPCC publishes a report which claims “increasing greenhouse gas emissions will enhance the greenhouse effect, resulting on average in an additional warming of the Earth’s surface.” It says an immediate 60% reduction in CO2 emissions would stop the buildup of carbon dioxide.

1994: More than 50 nations sign up to the United Nations Framework Convention on Climate Change. Australia is a signatory. 

1997: Near-global consensus is reached on the need for action over carbon emissions, leading to 160 nations signing the Kyoto Protocol on climate change. Like the United States, Australia signs the Protocol but refuses to ratify it.

2000: Environmental Defense reports: “Nations meeting in The Hague, Netherlands fail to reach agreement on the implementation rules that are prerequisites for most industrialized nations’ ratification of the Kyoto Protocol. Atmospheric concentrations of CO2 measured at Mauna Loa reach 368.37 ppm, their highest level in 420,000 years.”

2001: The IPCC released its Third Assessment Report, claiming that “there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.”

2002: Second hottest year ever recorded, following 1998.

2006: Global debate over climate change steps into the mainstream after Al Gores’s film An Inconvenient Truth hits cinemas.

August 2006: Australian Prime Minister John Howard tells Four Corners: “I don’t reject the climate change argument out of hand. I accept the broad consensus if you like but I am very sceptical of some of the Doomsday scenarios and this area is laden with Doomsayers.”

February 2007: The IPCC releases a statement claiming with 90% certainty that humans are the main cause of global warming since 1950.

March 2007: Federal Environment minister Malcolm Turnbull reveals he has been alert to the dangers detailed in the upcoming IPCC report. See above quote.

April 2007: The IPCC releases its latest report, upgrading its warning from 2001 on the dangers of global warming. 

Based on a timeline published by Environmental Defense.

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