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Global warming
Global warming is the increase in the average temperature of the Earth's
near-surface air and oceans in recent decades and its projected
continuation.
Global average air temperature near the Earth's surface rose 0.74 ± 0.18 °C
(1.33 ± 0.32 °F) during the past century. The Intergovernmental Panel on
Climate Change (IPCC) concludes, "most of the observed increase in globally
averaged temperatures since the mid-20th century is very likely due to the
observed increase in anthropogenic greenhouse gas concentrations,"[1] which
leads to warming of the surface and lower atmosphere by increasing the
greenhouse effect. Natural phenomena such as solar variation combined with
volcanoes have probably had a small warming effect from pre-industrial times
to 1950, but a small cooling effect since 1950.[2][3] These basic
conclusions have been endorsed by at least 30 scientific societies and
academies of science, including all of the national academies of science of
the major industrialized countries. The American Association of Petroleum
Geologists is the only scientific society that rejects these
conclusions.[4][5] A few individual scientists disagree with some of the
main conclusions of the IPCC.[6]
Climate models referenced by the IPCC project that global surface
temperatures are likely to increase by 1.1 to 6.4 °C (2.0 to 11.5 °F)
between 1990 and 2100.[1] The range of values reflects the use of differing
scenarios of future greenhouse gas emissions and results of models with
differences in climate sensitivity. Although most studies focus on the
period up to 2100, warming and sea level rise are expected to continue for
more than a millennium even if greenhouse gas levels are stabilized.[1] This
reflects the large heat capacity of the oceans.
An increase in global temperatures may in turn cause other changes,
including sea level rise, and changes in the amount and pattern of
precipitation resulting in floods and drought.[7] There may also be changes
in the frequency and intensity of extreme weather events, though it is
difficult to connect specific events to global warming. Other effects may
include changes in agricultural yields, glacier retreat, reduced summer
streamflows, species extinctions and increases in the ranges of disease
vectors.
Remaining scientific uncertainties include the exact degree of climate
change expected in the future, and how changes will vary from region to
region around the globe. There is ongoing political and public debate
regarding what, if any, action should be taken to reduce or reverse future
warming or to adapt to its expected consequences. Most national governments
have signed and ratified the Kyoto Protocol aimed at combating greenhouse
gas emissions.
Terminology
The term "global warming" is a specific example of the broader term climate
change, which can also refer to global cooling. In common usage the term
refers to recent warming and implies a human influence.[8] The United
Nations Framework Convention on Climate Change (UNFCCC) uses the term
"climate change" for human-caused change, and "climate variability" for
other changes.[9] The term "anthropogenic climate change" is sometimes used
when focusing on human-induced changes.
Causes
The climate system varies through natural, internal processes and in
response to variations in external forcing factors including solar activity,
volcanic emissions, variations in the earth's orbit (orbital forcing) and
greenhouse gases. The detailed causes of the recent warming remain an active
field of research, but the scientific consensus[10] identifies increased
levels of greenhouse gases due to human activity as the main influence. This
attribution is clearest for the most recent 50 years, for which the most
detailed data are available. Contrasting with the scientific consensus,
other hypotheses have been proposed to explain most of the observed increase
in global temperatures. One such hypothesis is that the warming is caused by
natural fluctuations in the climate or that warming is mainly a result of
variations in solar radiation.[11]
None of the effects of forcing are instantaneous. Due to the thermal inertia
of the Earth's oceans and slow responses of other indirect effects, the
Earth's current climate is not in equilibrium with the forcing imposed.
Climate commitment studies indicate that even if greenhouse gases were
stabilized at present day levels, a further warming of about 0.5 °C (0.9 °F)
would still occur.[12]
Greenhouse gases in the atmosphere
Recent increases in atmospheric carbon dioxide (CO2). The monthly CO2
measurements display small seasonal oscillations in an overall yearly
uptrend; each year's maximum is reached during the northern hemisphere's
late spring, and declines during the northern hemisphere growing season as
plants remove some CO2 from the atmosphere.
Recent increases in atmospheric carbon dioxide (CO2). The monthly CO2
measurements display small seasonal oscillations in an overall yearly
uptrend; each year's maximum is reached during the northern hemisphere's
late spring, and declines during the northern hemisphere growing season as
plants remove some CO2 from the atmosphere.
The greenhouse effect was discovered by Joseph Fourier in 1824 and was first
investigated quantitatively by Svante Arrhenius in 1896. It is the process
by which absorption and emission of infrared radiation by atmospheric gases
warms a planet's atmosphere and surface.
Greenhouse gases create a natural greenhouse effect, without which mean
temperatures on Earth would be an estimated 30 °C (54 °F) lower so that
Earth would be uninhabitable.[13] Thus scientists do not "believe in" or
"oppose" the greenhouse effect as such; rather, the debate concerns the net
effect of the addition of greenhouse gases, while allowing for associated
positive and negative feedback mechanisms.
On Earth, the major natural greenhouse gases are water vapor, which causes
about 36–70% of the greenhouse effect (not including clouds); carbon dioxide
(CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and ozone,
which causes 3–7%.[14][15] Some other naturally occurring gases contribute
very small fractions of the greenhouse effect; one of these, nitrous oxide
(N2O), is increasing in concentration owing to human activity such as
agriculture. The atmospheric concentrations of CO2 and CH4 have increased by
31% and 149% respectively above pre-industrial levels since 1750. These
levels are considerably higher than at any time during the last 650,000
years, the period for which reliable data has been extracted from ice cores.
From less direct geological evidence it is believed that CO2 values this
high were last attained 20 million years ago.[16] "About three-quarters of
the anthropogenic [man-made] emissions of CO2 to the atmosphere during the
past 20 years are due to fossil fuel burning. The rest of the anthropogenic
emissions are predominantly due to land-use change, especially
deforestation."[17]
The present atmospheric concentration of CO2 is about 383 parts per million
(ppm) by volume.[18] Future CO2 levels are expected to rise due to ongoing
burning of fossil fuels and land-use change. The rate of rise will depend on
uncertain economic, sociological, technological, natural developments, but
may be ultimately limited by the availability of fossil fuels. The IPCC
Special Report on Emissions Scenarios gives a wide range of future CO2
scenarios, ranging from 541 to 970 ppm by the year 2100.[19] Fossil fuel
reserves are sufficient to reach this level and continue emissions past
2100, if coal, tar sands or methane clathrates are extensively used.[20]
Positive feedback effects such as the expected release of CH4 from the
melting of permafrost peat bogs in Siberia (possibly up to 70,000 million
tonnes) may lead to significant additional sources of greenhouse gas
emissions[21] not included in climate models cited by the IPCC.[1]
Feedbacks
The effects of forcing agents on the climate are complicated by various
feedback processes.
One of the most pronounced feedback effects relates to the evaporation of
water. In the case of warming by the addition of long-lived greenhouse gases
such as CO2, the initial warming by these gases will cause more water to be
evaporated into the atmosphere. Since water vapor itself acts as a
greenhouse gas, this causes still more warming; the warming causes more
water vapor to be evaporated, and so forth until a new dynamic equilibrium
concentration of water vapor is reached with a much larger greenhouse effect
than that due to CO2 alone. (Although this feedback process involves an
increase in the absolute moisture content of the air, the relative humidity
stays nearly constant or even decreases slightly because the air is
warmer.)[22] This feedback effect can only be reversed slowly as CO2 has a
long average atmospheric lifetime.
Feedback effects due to clouds are an area of ongoing research and debate.
Seen from below, clouds emit infrared radiation back to the surface, and so
exert a warming effect. Seen from above, the same clouds reflect sunlight
and emit infrared radiation to space, and so exert a cooling effect.
Increased global water vapor concentration may or may not cause an increase
in global average cloud cover. The net effect of clouds thus has not been
well modeled, however, cloud feedback is second only to water vapor feedback
and is positive in all the models that were used in the IPCC Fourth
Assessment Report.[22]
Another important feedback process is ice-albedo feedback.[23] When global
temperatures increase, ice near the poles melt at an increasing rate. As the
ice melts, land or open water takes its place. Both land and open water are
on average less reflective than ice, and thus absorb more solar radiation.
This causes more warming, which in turn causes more melting, and this cycle
continues.
Positive feedback due to release of CO2 and CH4 from thawing permafrost is
an additional mechanism contributing to warming. Possible positive feedback
due to CH4 release from melting seabed ices is a further mechanism to be
considered.
The ocean's ability to sequester carbon is expected to decline as it warms,
because the resulting low nutrient levels of the mesopelagic zone limits the
growth of diatoms in favour of smaller phytoplankton that are poorer
biological pumps of carbon.[24]
Solar variation
Variations in solar output, possibly amplified by cloud feedbacks, may have
contributed to recent warming.[25] A difference between this mechanism and
greenhouse warming is that an increase in solar activity should produce a
warming of the stratosphere while greenhouse warming should produce a
cooling of the stratosphere. Reduction of stratospheric ozone also has a
cooling influence but substantial ozone depletion did not occur until the
late 1970s. Cooling in the lower stratosphere has been observed since at
least 1960.[26] Thus, solar activity alone is not the main contributor to
recent warming.
Phenomena such as solar variation combined with volcanoes have probably had
a warming effect from pre-industrial times to 1950, but a cooling effect
since 1950.[1] However, some research has suggested that the Sun's
contribution may have been underestimated. Two researchers at Duke
University have estimated that the Sun may have contributed about 40–50% of
the global surface temperature warming over the period 1900–2000, and about
25–35% between 1980 and 2000.[27] Stott and coauthors suggest that climate
models overestimate the relative effect of greenhouse gases compared to
solar forcing; they also suggest that the cooling effects of volcanic dust
and sulfate aerosols have been underestimated.[28] Nevertheless, they
conclude that even with an enhanced climate sensitivity to solar forcing,
most of the warming during the latest decades is attributable to the
increases in greenhouse gases.
More studies on the extent of warming caused by changes in the brightness of
the sun have been conducted. Scientists from the United States, Germany, and
Switzerland under Heliophysics, Inc. and the National Science Foundation
calculated that there has been no net increase of brightness over the last
thousand years.[29] All increases in brightness were the result of solar
cycles, and the small increase in brightness over the last 30 years is .07
percent. Scientists say that this small increase is far too minute to
contribute to global warming.
History
From the present to the dawn of human settlement
Global temperatures on both land and sea have increased by 0.75 °C (1.35 °F)
relative to the period 1860–1900, according to the instrumental temperature
record. This measured temperature increase is not significantly affected by
the urban heat island. Since 1979, land temperatures have increased about
twice as fast as ocean temperatures (0.25 °C per decade against 0.13 °C per
decade).[30] Temperatures in the lower troposphere have increased between
0.12 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to
satellite temperature measurements. Temperature is believed to have been
relatively stable over the one or two thousand years before 1850, with
possibly regional fluctuations such as the Medieval Warm Period or the
Little Ice Age.
Based on estimates by NASA's Goddard Institute for Space Studies, 2005 was
the warmest year since reliable, widespread instrumental measurements became
available in the late 1800s, exceeding the previous record set in 1998 by a
few hundredths of a degree.[31] Estimates prepared by the World
Meteorological Organization and the Climatic Research Unit concluded that
2005 was the second warmest year, behind 1998.[32][33]
Anthropogenic emissions of other pollutants—notably sulfate aerosols—can
exert a cooling effect by increasing the reflection of incoming sunlight.
This partially accounts for the cooling seen in the temperature record in
the middle of the twentieth century,[34] though the cooling may also be due
in part to natural variability.
Paleoclimatologist William Ruddiman has argued that human influence on the
global climate began around 8,000 years ago with the start of forest
clearing to provide land for agriculture and 5,000 years ago with the start
of Asian rice irrigation.[35] Ruddiman's interpretation of the historical
record, with respect to the methane data, has been disputed.[36]
Pre-human climate variations
Earth has experienced warming and cooling many times in the past. The recent
Antarctic EPICA ice core spans 800,000 years, including eight glacial cycles
timed by orbital variations with interglacial warm periods comparable to
present temperatures.[37]
A rapid buildup of greenhouse gases caused warming in the early Jurassic
period (about 180 million years ago), with average temperatures rising by 5
°C (9 °F). Research by the Open University indicates that the warming caused
the rate of rock weathering to increase by 400%. As such weathering locks
away carbon in calcite and dolomite, CO2 levels dropped back to normal over
roughly the next 150,000 years.[38][39]
Sudden releases of methane from clathrate compounds (the clathrate gun
hypothesis) have been hypothesized as a cause for other warming events in
the distant past, including the Permian-Triassic extinction event (about 251
million years ago) and the Paleocene-Eocene Thermal Maximum (about 55
million years ago).
Climate models
Scientists have studied global warming with computer models of the climate.
These models are based on physical principles of fluid dynamics, radiative
transfer, and other processes, with some simplifications being necessary
because of limitations in computer power. These models predict that the net
effect of adding greenhouse gases is to produce a warmer climate. However,
even when the same assumptions of fossil fuel consumption and CO2 emission
are used, the amount of projected warming varies between models and there
still remains a considerable range of climate sensitivity.
Including uncertainties in future greenhouse gas concentrations and climate
modelling, the IPCC anticipates a warming of 1.1 °C to 6.4 °C (2.0 °F to
11.5 °F) between 1990 and 2100.[1] Models have also been used to help
investigate the causes of recent climate change by comparing the observed
changes to those that the models project from various natural and human
derived causes.
Climate models can produce a good match to observations of global
temperature changes over the last century, but cannot yet simulate all
aspects of climate.[40] These models do not unambiguously attribute the
warming that occurred from approximately 1910 to 1945 to either natural
variation or human effects; however, they suggest that the warming since
1975 is dominated by man-made greenhouse gas emissions.
Most global climate models, when run to project future climate, are forced
by imposed greenhouse gas scenarios, generally one from the IPCC Special
Report on Emissions Scenarios (SRES). Less commonly, models may be run by
adding a simulation of the carbon cycle; this generally shows a positive
feedback, though this response is uncertain (under the A2 SRES scenario,
responses vary between an extra 20 and 200 ppm of CO2). Some observational
studies also show a positive feedback.[41][42][43]
The representation of clouds is one of the main sources of uncertainty in
present-generation models, though progress is being made on this
problem.[44] There is also an ongoing discussion as to whether climate
models are neglecting important indirect and feedback effects of solar
variability.
Attributed and expected effects
Some effects on both the natural environment and human life are, at least in
part, already being attributed to global warming. A 2001 report by the IPCC
suggests that glacier retreat, ice shelf disruption such as the Larsen Ice
Shelf, sea level rise, changes in rainfall patterns, increased intensity and
frequency of extreme weather events, are being attributed in part to global
warming.[45] While changes are expected for overall patterns, intensity, and
frequencies, it is difficult to attribute specific events to global warming.
Other expected effects include water scarcity in some regions and increased
precipitation in others, changes in mountain snowpack, adverse health
effects from warmer temperatures.
Increasing deaths, displacements, and economic losses projected due to
extreme weather attributed to global warming may be exacerbated by growing
population densities in affected areas, although temperate regions are
projected to experience some minor benefits, such as fewer deaths due to
cold exposure.[46] A summary of probable effects and recent understanding
can be found in the report made for the IPCC Third Assessment Report by
Working Group II.[45] The newer IPCC Fourth Assessment Report summary
reports that there is observational evidence for an increase in intense
tropical cyclone activity in the North Atlantic Ocean since about 1970, in
correlation with the increase in sea surface temperature, but that the
detection of long-term trends is complicated by the quality of records prior
to routine satellite observations. The summary also states that there is no
clear trend in the annual worldwide number of tropical cyclones.[1]
Additional anticipated effects include sea level rise of 110 to 770
millimeters (0.36 to 2.5 ft) between 1990 and 2100,[47] repercussions to
agriculture, possible slowing of the thermohaline circulation, reductions in
the ozone layer, increased intensity and frequency of hurricanes and extreme
weather events, lowering of ocean pH, and the spread of diseases such as
malaria and dengue fever. One study predicts 18% to 35% of a sample of 1,103
animal and plant species would be extinct by 2050, based on future climate
projections.[48] Two populations of Bay checkerspot butterfly are being
threatened by changes in precipitation, though few mechanistic studies have
documented extinctions due to recent climate change.[49]
Economics
Some economists have tried to estimate the aggregate net economic costs of
damages from climate change across the globe. Such estimates have so far
failed to reach conclusive findings; in a survey of 100 estimates, the
values ran from US$-10 per tonne of carbon (tC) (US$-3 per tonne of carbon
dioxide) up to US$350/tC (US$95 per tonne of carbon dioxide), with a mean of
US$43 per tonne of carbon (US$12 per tonne of carbon dioxide).[46] One
widely-publicized report on potential economic impact is the Stern Review;
it suggests that extreme weather might reduce global gross domestic product
by up to 1%, and that in a worst case scenario global per capita consumption
could fall 20%.[50] The report's methodology, advocacy and conclusions has
been criticized by many economists, primarily around the Review's
assumptions of discounting and its choices of scenarios.[51] , while others
have supported the general attempt to quantify economic risk, even if not
the specific numbers[52] [53].
In a summary of economic cost associated with climate change, the United
Nations Environment Programme emphasizes the risks to insurers, reinsurers,
and banks of increasingly traumatic and costly weather events. Other
economic sectors likely to face difficulties related to climate change
include agriculture and transport. Developing countries, rather than the
developed world, are at greatest economic risk.[54]
Mitigation and adaptation
The broad agreement among climate scientists that global temperatures will
continue to increase has led nations, states, corporations and individuals
to implement actions to try to curtail global warming or adjust to it. Many
environmental groups encourage action against global warming, often by the
consumer, but also by community and regional organizations. There has been
business action on climate change, including efforts at increased energy
efficiency and (still limited) moves to alternative fuels. One important
innovation has been the development of greenhouse gas emissions trading
through which companies, in conjunction with government, agree to cap their
emissions or to purchase credits from those below their allowances.
The world's primary international agreement on combating global warming is
the Kyoto Protocol, an amendment to the United Nations Framework Convention
on Climate Change (UNFCCC), negotiated in 1997. The Protocol now covers more
than 160 countries globally and over 55% of global greenhouse gas
emissions.[55] The United States (historically the world's largest
greenhouse gas emitter), Australia, and Kazakhstan have not ratified the
treaty. China and India, two other large emitters, have ratified the treaty,
but as developing countries, are exempt from its provisions. Chinese Premier
Wen Jiabao has called on the nation to redouble its efforts to tackle
pollution and global warming [56]
This treaty expires in 2012, and international talks began in May 2007 on a
future treaty to succeed the current one.[57]
The world's primary body for crafting a response is the Intergovernmental
Panel on Climate Change (IPCC), a UN-sponsored activity which holds periodic
meetings between national delegations on the problems of global warming, and
issues working papers and assessments on the current status of the science
of climate change, impacts, and mitigation. It convenes four different
working groups examining various specific issues. For example, in May 2007,
the IPCC held conferences in Bonn, Germany,[58] and in Bangkok,
Thailand.[59]
Issue debate and political processes
Increased awareness of the scientific findings surrounding global warming
has resulted in political and economic debate. Poor regions, particularly
Africa, appear at greatest risk from the suggested effects of global
warming, while their actual emissions have been negligible compared to the
developed world[60]. At the same time, developing country exemptions from
provisions of the Kyoto Protocol have been criticized by the United States
and have been used as part of its justification for continued
non-ratification.[61] In the Western world, the idea of human influence on
climate and efforts to combat it has gained wider acceptance in Europe than
in the United States.[62][63]
Fossil fuel companies such as ExxonMobil and some think tanks such as the
Competitive Enterprise Institute and the Cato Institute have campaigned to
downplay the risks of climate change,[64][65] while environmental groups and
entertainers have launched campaigns emphasizing the risks. Recently, some
fossil fuel companies have scaled back such efforts[66] or called for
policies to reduce global warming.[67]
This issue has sparked debate in the U.S. about the benefits of limiting
industrial emissions of greenhouse gases to reduce impacts to the climate,
versus the effects on economic activity.[68][69] There has also been
discussion in several countries about the cost of adopting alternate,
cleaner energy sources in order to reduce emissions.[70]
Another point of debate is the degree to which newly-developed economies,
like India and China, should be expected to constrain their emissions.
China's CO2 emissions are expected to exceed those of the U.S. within the
next few years (and according to one report may have already done so[71]).
Related climatic issues
A variety of issues are often raised in relation to global warming. One is
ocean acidification. Increased atmospheric CO2 increases the amount of CO2
dissolved in the oceans.[72] CO2 dissolved in the ocean reacts with water to
form carbonic acid resulting in acidification. Ocean surface pH is estimated
to have decreased from approximately 8.25 to 8.14 since the beginning of the
industrial era,[73] and it is estimated that it will drop by a further 0.14
to 0.5 units by 2100 as the ocean absorbs more CO2.[1][74] Since organisms
and ecosystems are adapted to a narrow range of pH, this raises extinction
concerns, directly driven by increased atmospheric CO2, that could disrupt
food webs and impact human societies that depend on marine ecosystem
services.[75]
Another related issue that may have partially mitigated global warming in
the late twentieth century is global dimming, the gradual reduction in the
amount of global direct irradiance at the Earth's surface. From 1960 to 1990
human-caused aerosols likely precipitated this effect. Scientists have
stated with 66–90% confidence that the effects of human-caused aerosols,
along with volcanic activity, have offset some of global warming, and that
greenhouse gases would have resulted in more warming than observed if not
for these dimming agents.[1]
Ozone depletion, the steady decline in the total amount of ozone in Earth's
stratosphere, is frequently cited in relation to global warming. Although
there are areas of linkage, the relationship between the two is not strong.
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Further reading
* Amstrup, Steven C.; Ian Stirling, Tom S. Smith, Craig Perham, Gregory W.
Thiemann (2006-04-27). "Recent observations of intraspecific predation and
cannibalism among polar bears in the southern Beaufort Sea". Polar Biology
29 (11): 997–1002. DOI:10.1007/s00300-006-0142-5.
* Association of British Insurers (2005-06). Financial Risks of Climate
Change (PDF).
* Barnett, Tim P.; J. C. Adam, D. P. Lettenmaier (2005-11-17). "Potential
impacts of a warming climate on water availability in snow-dominated
regions". Nature 438 (7066): 303–309. DOI:10.1038/nature04141.
* Behrenfeld, Michael J.; Robert T. O'Malley, David A. Siegel, Charles R.
McClain, Jorge L. Sarmiento, Gene C. Feldman, Allen G. Milligan, Paul G.
Falkowski, Ricardo M. Letelier, Emanuel S. Boss (2006-12-07).
"Climate-driven trends in contemporary ocean productivity" (PDF). Nature 444
(7120): 752–755. DOI:10.1038/nature05317.
* Choi, Onelack; Ann Fisher (May 2005). "The Impacts of Socioeconomic
Development and Climate Change on Severe Weather Catastrophe Losses:
Mid-Atlantic Region (MAR) and the U.S.". Climate Change 58 (1–2): 149–170.
DOI:10.1023/A:1023459216609.
* Dyurgerov, Mark B.; Mark F. Meier (2005). Glaciers and the Changing Earth
System: a 2004 Snapshot (PDF), Institute of Arctic and Alpine Research
Occasional Paper #58. ISSN 0069-6145.
* Emanuel, Kerry A. (2005-08-04). "Increasing destructiveness of tropical
cyclones over the past 30 years." (PDF). Nature 436 (7051): 686–688.
DOI:10.1038/nature03906.
* Hansen, James; Larissa Nazarenko, Reto Ruedy, Makiko Sato, Josh Willis,
Anthony Del Genio, Dorothy Koch, Andrew Lacis, Ken Lo, Surabi Menon, Tica
Novakov, Judith Perlwitz, Gary Russell, Gavin A. Schmidt, Nicholas Tausnev
(2005-06-03). "Earth's Energy Imbalance: Confirmation and Implications"
(PDF). Science 308 (5727): 1431–1435. DOI:10.1126/science.1110252.
* Hinrichs, Kai-Uwe; Laura R. Hmelo, Sean P. Sylva (2003-02-21). "Molecular
Fossil Record of Elevated Methane Levels in Late Pleistocene Coastal
Waters". Science 299 (5610): 1214–1217. DOI:10.1126/science.1079601.
* Hirsch, Tim. "Plants revealed as methane source", BBC, 2006-01-11.
* Hoyt, Douglas V.; Kenneth H. Schatten (1993–11). "A discussion of
plausible solar irradiance variations, 1700–1992". Journal of Geophysical
Research 98 (A11): 18,895–18,906.
* Kenneth, James P.; Kevin G. Cannariato, Ingrid L. Hendy, Richard J. Behl
(2003-02-14). Methane Hydrates in Quaternary Climate Change: The Clathrate
Gun Hypothesis. American Geophysical Union.
* Keppler, Frank, Marc Brass, Jack Hamilton, Thomas Röckmann. "Global
Warming - The Blame Is not with the Plants", Max Planck Society, 2006-01-18.
* Kurzweil, Raymond (2006–07). "Nanotech Could Give Global Warming a Big
Chill" (PDF). Forbes / Wolfe Nanotech Report 5 (7).
* Lean, Judith L.; Y.M. Wang, N.R. Sheeley (2002–12). "The effect of
increasing solar activity on the Sun's total and open magnetic flux during
multiple cycles: Implications for solar forcing of climate". Geophysical
Research Letters 29 (24). DOI:10.1029/2002GL015880.
* Lerner, K. Lee; Brenda Wilmoth Lerner (2006-07-26). Environmental issues :
essential primary sources.. Thomson Gale. ISBN 1414406258.
* McLaughlin, Joseph B.; Angelo DePaola, Cheryl A. Bopp, Karen A. Martinek,
Nancy P. Napolilli, Christine G. Allison, Shelley L. Murray, Eric C.
Thompson, Michele M. Bird, John P. Middaugh (2005-10-06). "Outbreak of
Vibrio parahaemolyticus gastroenteritis associated with Alaskan oysters".
New England Journal of Medicine 353 (14): 1463–1470. (online version
requires registration)
* Muscheler, Raimund; Fortunat Joos, Simon A. Müller, Ian Snowball
(2005-07-28). "Climate: How unusual is today's solar activity?" (PDF).
Nature 436 (7012): 1084–1087. DOI:10.1038/nature04045.
* Oerlemans, J. (2005-04-29). "Extracting a Climate Signal from 169 Glacier
Records" (PDF). Science 308 (5722): 675–677. DOI:10.1126/science.1107046.
* Oreskes, Naomi (2004-12-03). "Beyond the Ivory Tower: The Scientific
Consensus on Climate Change" (PDF). Science 306 (5702): 1686.
DOI:10.1126/science.1103618.
* Purse, Bethan V.; Philip S. Mellor, David J. Rogers, Alan R. Samuel, Peter
P. C. Mertens, Matthew Baylis (February 2005). "Climate change and the
recent emergence of bluetongue in Europe". Nature Reviews Microbiology 3
(2): 171–181. DOI:10.1038/nrmicro1090.
* Revkin, Andrew C. "Rise in Gases Unmatched by a History in Ancient Ice",
The New York Times, 2005-11-05.
* Ruddiman, William F. (2005-12-15). Earth's Climate Past and Future. New
York: Princeton University Press. ISBN 0-7167-3741-8.
* Ruddiman, William F. (2005-08-01). Plows, Plagues, and Petroleum: How
Humans Took Control of Climate. New Jersey: Princeton University Press. ISBN
0-691-12164-8.
* Solanki, Sami K.; I.G. Usoskin, B. Kromer, M. Schussler, J. Beer
(2004-10-23). "Unusual activity of the Sun during recent decades compared to
the previous 11,000 years." (PDF). Nature 431: 1084–1087.
DOI:10.1038/nature02995.
* Solanki, Sami K.; I. G. Usoskin, B. Kromer, M. Schüssler, J. Beer
(2005-07-28). "Climate: How unusual is today's solar activity? (Reply)"
(PDF). Nature 436: E4-E5. DOI:10.1038/nature04046.
* Sowers, Todd (2006-02-10). "Late Quaternary Atmospheric CH4 Isotope Record
Suggests Marine Clathrates Are Stable". Science 311 (5762): 838–840.
DOI:10.1126/science.1121235.
* Svensmark, Henrik; Jens Olaf P. Pedersen, Nigel D. Marsh, Martin B.
Enghoff, Ulrik I. Uuggerhøj (2007-02-08). "Experimental evidence for the
role of ions in particle nucleation under atmospheric conditions".
Proceedings of the Royal Society A 463 (2078): 385–396.
DOI:10.1098/rspa.2006.1773. (online version requires registration)
* Walter, K. M.; S. A. Zimov, Jeff P. Chanton, D. Verbyla, F. S. Chapin
(2006-09-07). "Methane bubbling from Siberian thaw lakes as a positive
feedback to climate warming". Nature 443 (7107): 71–75.
DOI:10.1038/nature05040.
* Wang, Y.-M.; J.L. Lean, N.R. Sheeley (2005-05-20). "Modeling the sun's
magnetic field and irradiance since 1713" (PDF). Astrophysical Journal 625:
522–538. DOI:10.1086/429689.
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