While I am at it, here is a timeline on global warming from the Environmental Defense Fund. I thought the history and evolution were fascinating, although it is a couple of years out of date. Since 1997, each subsequent year has been even hotter:
Global Warming: The History
of an International Scientific Consensus
1896
Arrhenius, a Swedish chemist, advances the theory that carbon dioxide emissions from
combustion of coal would enhance Earth's greenhouse effect and lead to global warming.
1924
Based on 1920 coal use, Lotka, a U.S. physicist, speculates that industrial activity will double
atmospheric CO 2 in 500 years.
1949
Callendar, a British scientist, speculatively links the estimated 10% increase of atmospheric
CO 2 between 1850 and 1940 with the observed warming of northern Europe and North
America which began in the 1880's.
1954
Hutchinson, a Yale biologist, first suggests that deforestation will increase atmospheric CO 2 .
1957
Revelle and Seuss, scientists with the Scripps Institute of Oceanography, report for the first
time that much of the CO 2 emitted to the atmosphere is not absorbed by the oceans, as
some had argued, leaving significant amounts in the atmosphere which could eventually warm
the Earth. They call carbon dioxide emissions "a large-scale geophysical experiment" with
Earth's climate.
1958
Keeling, a scientist with the Scripps Institute, begins the first reliable and continuous
measurements of atmospheric carbon dioxide at Hawaii's Mauna Loa Observatory.
1967
The first reliable computer simulation calculates that global average temperature may increase
by more than 4 degrees fahrenheit when the atmospheric CO 2 level doubles that of
preindustrial times.
1971
Some scientists argue that cooling of the atmosphere by particulates from coal burning could
be more significant than warming by greenhouse gases. Uncertainties are too large to be sure
which effect will dominate.
1976
Scientists at several research institutions identify chlorofluorocarbons (CFCs), methane, and
nitrous oxide as greenhouse gases.
1976
U.S. and Swedish scientists estimate that cooling by particlulates from coal burning is a
relatively small effect on a global average basis.
1979
The report of a National Academy of Sciences (NAS) panel on climate change advises that
"A wait-and-see policy may mean waiting until it is too late" to avoid significant climate
changes.
1983
An NAS report confirms that a doubling of CO 2 levels eventually would warm the Earth by
3 to 8 degrees fahrenheit. The same year a U.S. Environmental Protection Agency (EPA)
study called Can We Delay A Greenhouse Warming? states that as a result of warming,
"agricultural conditions will be significantly altered, environmental and economic systems
potentially disrupted, and political institutions stressed."
1985
A conference sponsored by the United Nations Environment Program (UNEP), the World
Meteorological Organization (WMO), and the International Council of Scientific Unions
forges a consensus of the international scientific community on the issue of climate change.
The conference report warns that some future warming appears inevitable due to past
emissions regardless of future actions and recommends consideration of a global treaty to
address climatic change.
1987
An ice core from Antarctica analyzed by French and Russian scientists reveals an extremely
close correlation between CO 2 and temperature going back more than 100,000 years.
1988
The Intergovernmental Panel on Climate Change (IPCC), made up of leading climate
scientists from around the world, is established by UNEP and WMO to assess the scientific
and economic basis of climate change policy in preparation for the 1992 Rio Earth Summit.
1990
An appeal signed by 49 Nobel prize winners and 700 members of the NAS states, "There is
broad agreement within the scientific community that amplification of the Earth's natural
greenhouse effect by the buildup of various gases introduced by human activity has the
potential to produce dramatic changes in climate ... Only by taking action now can we insure
that future generations will not be put at risk."
The scientific working group of the IPCC, drawing on 170 scientists from 25 countries,
publishes a report stating that human activity increasing greenhouse gas emissions "will
enhance the greenhouse effect, resulting on average in an additional warming of the Earth's
surface." It calculates that an immediate 60% reduction in CO 2 emissions would stop the
buildup of carbon dioxide.
747 participants from 116 countries take part in the Second World Climate Conference. The
conference statement reports that "a clear scientific consensus has emerged on estimates of
the range of global warming which can be expected during the 21st century. If the increase of
greenhouse gas concentrations is not limited, the predicted climate change would place
stresses on natural and social systems unprecedented in the past 10,000 years."
1991
Mt. Pinatubo, a Philippine volcano, erupts, temporarily interrupting the increase in surface
temperatures.
1992
The NAS publishes a study reporting that despite uncertainties, greenhouse warming poses a
potential threat, "sufficient to merit prompt responses ... Investment in mitigation measures act
as insurance protection against the great uncertainties and the possibility of dramatic
surprises. In addition, the panel believes that substantial mitigation can be accomplished at
modest cost. In other words, insurance is cheap."
A supplementary IPCC report updating its 1990 study finds that new research confirms the
general conclusions of its earlier study. However, the report notes that reflection of sunlight
by particulates may be offsetting some greenhouse warming in the Northern hemisphere.
The United Nations Framework Convention on Climate Change is signed by 155 nations at
the Rio Earth Summit.
1993
The United Nations Framework Convention on Climate Change is ratified by more than 50
nations, putting it into effect. Efforts are currently underway to implement and strengthen it
world-wide.
1994
Mt. Pinatubo's cooling effect wanes, and Earth's temperature returns to high readings
characteristic of the late 1980's; March through December 1994 are the warmest such
period on record, according to the National Weather Service's Climate Analysis Center.
1995
The Intergovernmental Panel on Climate Change, representing the consensus of climate
scientists worldwide, concludes that "... the balance of evidence suggests that there is a
discernible human influence on global climate."
The year 1995 matches 1990 as the hottest year on record.
1997
Parties to the Framework Convention to meet in Kyoto, Japan, in December in order to
agree on binding obligations to limit emissions. |
