Article: "Solar Forcing of Regional Climate Change During the Maunder Minimum."
- During 1680-1780 global average temperature dropped about 0.3 to 0.4 degrees C. Regional temperature changes over continents were much larger, about -1 to -2 degrees C.
- Relatively small solar forcing may play significant role in century-scale Northern Hemisphere winter climate change.
- Little Ice Age and Medieval Warm Period may have been influenced by long term solar variations.
Source: Science, Volume 294, Number 5549.
Date: 2001 December 7
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Article: "Aerosol Effect on Cloud Droplet Size Monitored from Satellite."
- The effect of aerosols on cloud microphysics is significant and occurs on a global scale.
- Aerosol radiative forcing has a net cooling effect on climate.
- Aerosols in clouds increases number of droplets, reducing mean droplet size.
- Aerosols in clouds also suppresses rain.
- Satellite measurement cannot distinguish between natural and man-made aerosols.
- Large part of aerosol effect on clouds probably from man.
Source: Science, Volume 295, Number 5556.
Date: 2002 February 1
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Article: "Low-Frequency Signals in Long Tree-Ring Chronologies for Reconstructing Past Temperature Variability."
- Tree-ring chronologies can preserve coherent large-scale multicentennial temperature trends.
- These chronologies support large-scale occurrence of Medieval Warming Period over the Northern Hemisphere extratropics centered at 1000 AD.
- Strong evidence for below-average temperature over much of 1200-1850 AD.
- The 1000- to 2000-year climate rhythm in the North Atlantic ocean may be cause of multicentennial variations.
Source: Science, Volume 295, Number 5563.
Date: 2002 March 22
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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: "Interpretation of Recent Southern Hemisphere Climate Change."
- Ozone losses and increased greenhouse gasses over Antarctica have increased the westerly flow of the circumpolar vortex.
- This increased flow is contributing substantially to warming over Antarctic Peninsula and Patagonia, and cooling over eastern Antarctica and Antarctic plateau.
Source: Science, Volume 296, Number 5569.
Date: 2002 May 3
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Article: "The Cenozoic palaeoenvironment of the Arctic Ocean."
- Cooling of the Arctic 45 million years ago coincided with Antarctic cooling.
- Temperature of surface waters of Arctic 55 million years ago about 24 degrees C, ice-free and biologically productive.
Source: Nature, Volume 441, Number 7093.
Date: 2006 June 1
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Article: "Near-Synchronous Interhemispheric Termination of the Last Glacial Maximum in Mid-Latitudes."
- End of last glacial period initiated globally, with onset of atmospheric carbon dioxide.
- Global summer warming (17,000 to 19,000 years ago) may have destabilized Northern Hemisphere ice sheets, triggering iceberg discharge into North Atlantic.
- Fresh water input to Atlantic slowed the meridional overturning circulation, giving North Atlantic hypercold winters.
Source: Science, Volume 312, Number 5779.
Date: 2006 June 9
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Article: "Surface and Deep Ocean Interactions During the Cold Climate Event 8200 Years ago."
- 8490 years ago, freshwater from melting ice of the Laurentide Ice Sheet caused cooling of the North Atlantic, interrupting the meridional overturning circulation, causing cold climate in Europe.
- Another cooling occurred 8290 years ago.
Source: Science, Volume 312, Number 5782.
Date: 2006 June 30
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Article: "The Impact of Boreal Forest Fire on Climate Warming."
- Short term (first year) effect of boreal forest fire is increased radiative forcing 34 Watts per metre squared of burned area.
- Long term effect is decreased forcing by -2.3 Watts per square metre when averaged over 80 year fire cycle.
- Future increases in boreal fire may not accelerate climate warming.
Source: Science, Volume 314, Number 5802.
Date: 2006 November 17
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Article: "Gulf Stream density structure and transport during the past millennium."
Diminished oceanic heat transport during 1200-1850 may have contributed to North Atlantic cooling.
Source: Nature, Volume 444, Number 7119.
Date: 2006 November 30
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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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