Article: "Atmospheric CO2 Concentrations over the Last Glacial Termination."
- Correlation between CO2 concentration and Antarctic temperatures over 6000 years indicates Southern Ocean had important role in causing CO2 increase.
- Comparison of deuterium (proxy for temperature) and CO2 indicate lag of CO2 behind temperature change by 410 years.
- CO2 in the atmosphere rose from 189 ppmv to 265 in 6000 years.
Source: Science, Volume 291, Number 5501.
Date: 2001 January 5
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Article: "Tropical Origins for Recent North Atlantic Climate Change."
- North Atlantic climate change since 1950 is linked to warming of tropical sea surface temperatures.
- Oceans may be responding to solar forcing, as shown in data since 1000 AD.
- Oceans may also be responding to changes in atmosphere since 1950 due to human activities.
Source: Science, Volume 292, Number 5514.
Date: 2001 April 6
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Article: "Anthropogenic Warming of Earth's Climate System."
- Increased ocean heat since 1950 may largely be due to increase in anthropogenic gases in atmosphere.
- The dominant change in heat content of the Earth's climate system in the past fifty years is associated with the warming of the world ocean.
Source: Science, Volume 292, Number 5515.
Date: 2001 April 13
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Article: "Evidence for Substantial variations of Atmospheric Hydroxyl Radicals in the Past Two Decades."
- Atmospheric 1,1,1-trichloroethane rose steadily from 1978 to maximum in 1992, then decreased rapidly to 2000, to levels below 1978.
- Concentrations of hydroxyl in the atmosphere rose from 1978 to 1988 then declined to 2000. Hydroxyl (HO) is the dominant oxidizing chemical destroying most air pollutants and many gases involved in ozone depletion and the greenhouse effect.
- The present understanding of the capacity of the atmosphere to remove many man-made and natural trace gases is incomplete, with important implications for mitigation of air pollution and climate change.
Source: Science, Volume 292, Number 5523.
Date: 2001 June 8
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Article: "Paleobotanical Evidence for Near Present-Day Levels of Atmospheric CO2 During part of the Tertiary."
- Carbon dioxide levels in the atmosphere remained between 300-400 parts per million by volume during 14-18 million years ago, and 54-60 million years ago.
- Results suggest factors in addition to carbon dioxide are required to explain these past intervals of global warmth.
Source: Science, Volume 292, Number 5525.
Date: 2001 June 22
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Article: "Changes in Forest Biomass Carbon Storage in China Between 1949 and 1998."
Chinese forests released about 0.68 petagram of carbon between 1949-1980, then increased by 0.37 petagram by 1998.
Source: Science, Volume 292, Number 5525.
Date: 2001 June 22
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Article: "A Microphysical Connection Among Biomass Burning, Cumulus Clouds, and Stratospheric Moisture."
The increase in stratospheric water vapor since 1950 may be partly caused by topical biomass burning.
Source: Science, Volume 295, Number 5558.
Date: 2002 February 15
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Article: "Global Cooling After the Eruption of Mount Pinatubo: A Test of Climate Feedback by Water Vapor."
- Atmospheric general circulation models successfully reproduce observed drying of atmosphere after Mount Pinatubo eruption in June 1991.
- Atmospheric drying amplifies temperature change (cooling) due to increased aerosols in lower atmosphere.
Source: Science, Volume 296, Number 5568.
Date: 2002 April 26
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Article: "Climatic Control of the High-Latitude Vegetation Greening Trend and Pinatubo Effect."
- Gradual lengthening of growing season in high northern latitudes has resulted in greening trend.
- Following Mount Pinatubo volcano eruption in 1991, trend was interrupted, producing increased carbon sink, contributing to slowdown in global rate of atmospheric carbon dioxide growth.
Source: Science, Volume 296, Number 5573.
Date: 2002 May 31
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Article: "Super ENSO and Global Climate Oscillations at Millenial Time Scales."
- Since last glacial maximum, 22,000 years ago, sea surface temperatures of tropical Pacific ocean have warmed about 2 degrees Celcius (summer) and 3 degrees (winter).
- Variability of tropical Pacific temperature over past glacial period (22,000 years ago to 64,000 years ago) average 1-2 degrees celcius.
- In western tropical Pacific, ocean was saltier through much of past 70,000 years than today.
- Millennial-scale El Nino-like conditions may have shifted atmospheric convection away from west tropical Pacific, explaining lower atmospheric carbon dioxide, N2O, and methane during stadial periods.
Source: Science, Volume 297, Number 5579.
Date: 2002 July 12
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Article: "The search for signs of recovery of the ozone layer."
- Total column ozone has stopped decreasing over the past eight years for most of the world.
- It is unknown if ozone improvement is attributable to an observed decline in ozone-depleting substances in the Earth's atmosphere.
- It is unlikely for ozone levels to stabilize at levels observed before 1980.
Source: Nature, Volume 441, Number 7089.
Date: 2006 May 4
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Article: "Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing."
- Weakened surface winds have altered thermal structure and circulation of tropical Pacific Ocean.
- Climate models indicate cause is man-made.
Source: Nature, Volume 441, Number 7089.
Date: 2006 May 4
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Article: "Subtropical Arctic Ocean temperatures during the Palaeocene/Eocene thermal maximum."
- 55 million years ago was brief period of widespread, extreme climatic warming, with massive atmospheric climatic warming, with massive atmospheric greenhouse gas input.
- Sea surface temperatures near the North Pole increased from 18 degrees C to 23C during this event, implying an absence of ice, excluding influence of ice-albedo feedback on Arctic warming.
- Derived temperatures are 10 degrees C warmer than model predictions, suggesting other feedback mechanism must have been present, and are not currently incorporated in models.
Source: Nature, Volume 441, Number 7093.
Date: 2006 June 1
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Article: "The Pliocene Paradox (Mechanisms for a Permanent El Nino)."
- 3 to 5 million years ago, globally averaged temperatures were substantially higher than today, atmospheric carbon dioxide was similar, but surface temperature at poles was higher that Northern Hemisphere had no continental glaciers.
- Amplification of response of climate to orbital forcing began 3 million years ago, resulting in drastic oscillations between ice ages and warmer periods over the past 1 million years.
- El Nino was continual rather than intermittent up to 3 million years ago.
- A persistence of high carbon dioxide concentrations could result in return to globally warm world.
Source: Science, Volume 312, Number 5779.
Date: 2006 June 9
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Article: "The importance of the diurnal and annual cycle of air traffic for contrail radiative forcing."
- Air traffic condensation trails (contrails) have a small net atmospheric warming effect, trapping more outgoing longwave radiation than reflecting incoming solar radiation.
- Nighttime flights for a site in southeast England account for 25 percent of daily air traffic, but contribute 60-80 percent of contrail forcing.
- Winter (December to February) flights are 22 percent of traffic, but contribute 50 percent to annual mean contrail forcing.
- Shifting air traffic from night to day would minimize climate effect of contrails.
Source: Nature, Volume 441, Number 7095.
Date: 2006 June 15
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Article: "Permafrost and the Global Carbon Budget."
- Climate warming will thaw permafrost, releasing trapped carbon, about 100 gigatons.
- The Earth's atmosphere presently contains about 730 gigatons of carbon.
Source: Science, Volume 312, Number 5780.
Date: 2006 June 16
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Article: "Ice Record of Carbon Isotope 13 for Atmospheric Methane Across the Younger Dryas-Preboreal Transition."
- Methane isotope 13 in atmosphere was about one percent higher over Greenland 11,400 to 12,200 years ago than in modern atmosphere.
- Source likely tropical wetlands or aerobic plant methane production.
Source: Science, Volume 313, Number 5790.
Date: 2006 August 25
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Article: "Land-atmosphere coupling and climate change in Europe."
- Predicted increases in summer temperature variability in central and eastern Europe is mainly due to feedbacks between the land surface and the atmosphere.
- Enhanced greenhouse gas concentrations lead to a northwards shift of climate zones within the European continent.
Source: Nature, Volume 443, Number 7108.
Date: 2006 September 14
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Article: "Contribution of anthropogenic and natural sources to atmospheric methane variability."
- Atmospheric concentration of methane has nearly tripled since pre-industrial times.
- Growth rate declined since early 1990s, constant since 1999.
- Decrease in atmospheric methane growth during 1990s caused by decline in anthropogenic emissions.
- Since 1999, anthropogenic emissions rising again, though wetlands coincidentally decreasing.
Source: Nature, Volume 443, Number 7110.
Date: 2006 September 28
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Article: "Elevated Eocene Atmospheric Carbon Dioxide and Its Subsequent Decline."
- Temperature peaked 50-52 million years ago, when atmospheric CO2 ranged 1125-3000 parts per million.
- By 20 million years ago, CO2dropped to about 400 ppm.
Source: Science, Volume 313, Number 5795.
Date: 2006 September 29
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Article: "Rapid Early Development of Circumarctic Peatlands and Atmospheric Methane and Carbon Dioxide Variations."
- Development of current circumarctic peatlands began 16,500 years ago, expanded rapidly 8-12,000 years ago during high summer insolation and increasing temperature.
- Peatland development contributed to sustained peak of methane at 650 parts per billion for 1500 years.
- Decline in peatland initiation follows decline in atmospheric methane and carbon dioxide from 10,000 years ago to 6000 years ago.
- Decline in peatland initiation from 6000 years ago to 1700 A.D. does not follow rise in methane and carbon dioxide, so must have some other non-manmade source.
Source: Science, Volume 314, Number 5796.
Date: 2006 October 13
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Article: "A Combined Mitigation / Geoengineering Approach to Climate Stabilization."
- Deliberate injection of sulfate aerosols into the stratosphere could substantially offset future warming and provide additional time to reduce carbon dioxide levels.
Source: Science, Volume 314, Number 5798.
Date: 2006 October 20
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Article: "Negligible glacial-Interglacial variation in continental chemical weathering rates."
- Chemical weathering of the continents, which draws carbon dioxide into the oceans, does not differ greatly between glacial and interglacial periods.
- Enhanced weathering of silicate glacial sediments during interglacial periods results in net draw-down of atmospheric carbon dioxide, creating positive feedback on global climate, promoting cooling.
Source: Nature, Volume 444, Number 7121.
Date: 2006 December 14
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Article: "Effect of natural iron fertilization on carbon sequestration in the Southern Ocean."
- The Southern Ocean is most sensitive oceanic body to climate change.
- Iron fertilization of surface waters during glacial times by enhanced dust deposition may explain lower atmospheric CO2 during colder climates.
- Natural iron fertilization from below results in high carbon sequestration efficiency.
- Short-term iron addition experiments cannot be extrapolated to longer timescales.
Source: Nature, Volume 446, Number 7139.
Date: 2007 April 26
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Article: "Indirect radiative forcing of climate change through ozone effects on the land-carbon sink."
- Emissions due to fossil fuel and biomass burning about doubled global mean tropospheric ozone concentration.
- As increases in ozone concentrations negatively affect plant productivity, more CO2 accumulates in the atmosphere.
Source: Nature, Volume 448, Number 7155.
Date: 2007 August 16
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