Models Underestimate Future Warming

Woods Hole Oceanographic Institution
Lead author: Karen Bice
Where published: Paleoceanography, American Geophysical Union

Scientists have found evidence that tropical Atlantic Ocean temperatures may have once reached 107°F (42°C)—about 25°F (14°C) higher than ocean temperatures today and warmer than a hot tub. The surprisingly high ocean temperatures, the warmest estimates to date for any place on Earth, occurred millions of year ago when carbon dioxide levels in Earth’s atmosphere were also high, but researchers say they may be an indication that greenhouse gases could heat the oceans in the future much more than currently anticipated. The study suggests that climate models underestimate future warming.
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Significance of 20th Century Warming

University of East Anglia
Lead author: Timothy Osborn, Keith Briffa
Where published: Science

The most significant and longest duration feature during the last 1200 years is the geographical extent of warmth in the middle to late 20th century. Positive anomalies during 890 to 1170 and negative anomalies during 1580 to 1850 are consistent with the concepts of a Medieval Warm Period and a Little Ice Age, but comparison with instrumental temperatures shows the spatial extent of recent warmth to be of greater significance than that during the medieval period.

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Arctic Ice & Aerosols

Scripps Institute of Oceanography, Brookhaven National Laboratory, US Dept of Energy
Author: Dan Lubin
Where published: Nature Magazine

Enhanced aerosol concentrations increase the amount of thermal energy emitted by many Arctic clouds... The Arctic is showing the first unmistakable signs of climate warming caused by human activities, in the form of rapidly retreating and thinning sea ice
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Greenhouse Gas Levels

University of Bergen
Author: Thomas Stocker

Current levels of the greenhouse gases, carbon dioxide and methane, are higher now than they have ever been in 650,000 years
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Temperate Forests Might Not Help

Livermore Laboratory, Carnegie Institution
Lead author: Seran Gibbard
Where published: Geophysical Research Letters

Planting trees across the United States and Europe to absorb some of the carbon dioxide emitted by the burning of fossil fuels may just outweigh the positive effects of sequestering that CO².

In theory, growing a forest may sound like a good idea to fight global warming, but in temperate regions, such as the United States, those trees also would soak up sunlight, causing the earth’s surface to warm regionally by up to 8 degrees Fahrenheit.
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Sea Level Rising

Rutgers University
Lead author: Kenneth G. Miller
Where published: Science Magazine

Ocean levels are rising twice as fast today as they were 150 years ago, and human-induced warming appears to be the culprit
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Impact of Aerosols

Hadley Centre
Lead author: Nicolas Bellouin
Where published: Nature

New observations show that man-made aerosols may be having a greater direct effect on our climate than previously thought
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Predicted Water Shortages

Scripps Institution of Oceanography, University of Washington
Authors: Tim Barnett, Jennifer Adam, Dennis Lettenmaier
Where published: Nature

global warming will reduce glaciers and storage packs of snow in regions around the world, causing water shortages and other problems that will impact millions of people
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Atrmosphere/Surface Temp Reconciled

Yale University / National Oceanic and Atmospheric Administration
Lead author: Steven C. Sherwood
Where published: Science Magazine

direct heat of the sun on temperature probes of the weather balloon (radiosonde) probably explains the discrepancy between reports showing that atmospheric temperatures have been unchanged since the 1970’s, while temperatures at the Earth’s surface are rising ... Unfortunately, the warming is in an accelerating trend
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Anthropogenic Warming of Oceans

Scripps, Livermore Labs, Hadley Centre, NCAR
Lead author: Tim Barnett
Where published: Science

A warming signal has penetrated into the world's oceans over the past 40 years. The signal is complex, with a vertical structure that varies widely by ocean; it cannot be explained by natural internal climate variability or solar and volcanic forcing, but is well simulated by two anthropogenically forced climate models. We conclude that it is of human origin, a conclusion robust to observational sampling and model differences. Changes in advection combine with surface forcing to give the overall warming pattern. The implications of this study suggest that society needs to seriously consider model predictions of future climate change.

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Solar Activity Not Causing Warming

Meteorological Institute, Oslo, Norway
Lead author: R. E. Benestad
Where published: American Geophysical Union

no indication of a systematic trend in the level of solar activity that can explain the most recent global warming

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Glacier Retreat

British Antarctic Survey, U.S. Geological Survey
Lead author: Alison Cook
Where published: Science Magazine

over the last 50 years 87% of 244 glaciers studied have retreated, and that average retreat rates have accelerated
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Anthropogenic Ocean Warming

Scripps Institute of Oceanography, Livermore Labratories
Lead authors: Tim Barnett, David Pierce

results clearly indicate that the warming is produced anthropogenically ... The statistical significance of these results is far too strong to be merely dismissed and should wipe out much of the uncertainty about the reality of global warming.
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Kilimanjaro Glaciers Retreating

Ohio State University
Lead author: Lonnie Thompson

Five years after warning that the famed ice fields on Tanzania 's Mount Kilimanjaro may melt, Ohio State University researchers have sadly found that their prediction is coming true.

“The change there is so dramatic,” he [Lonnie Thompson] said. “We can see it both in the field and from aerial photographs of the mountaintop. I would say it is on track to disappear, and the rate of ice loss may even be accelerating.
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Warming Not From Urban Heat Islands

Hadley Centre
Lead author: David Parker
Where published: Nature

large-scale global warming is not a result of urban development... Measurements of night-time air temperature, averaged across a number of weather stations worldwide, show a rate of warming of around 0.19 °C per decade during the period 1950-2000. This rate is the same for calm conditions as it is for windy.
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Arctic Climate Impact Assessment

Arctic Council

Ice cores and other evidence of climate conditions in the distant past provide evidence that rising atmospheric carbon dioxide levels are associated with rising global temperatures. Human activities, primarily the burning of fossil fuels, and secondarily clearing of land, have increased the concentration of carbon dioxide, methane, and other heat-trapping ("greenhouse") gases in the atmosphere.

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Solar Variability Unlikely Caused Recent Warming

Max Planck Institute, U. Oulu
Lead Authors: S. K. Solanki, I. G. Usoskin
Where published: Nature

Solar variability is unlikely to have been the dominant cause of the strong warming during the past three decades

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Greenhouses Gases Explain Recent Warming

Hadley Centre
Lead authors: Peter Stott, Gareth Jones, John Mitchell

results confirm previous analyses showing that greenhouse gas increases explain most of the global warming observed in the second half of the twentieth century

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Warming Arctic Temperature

NASA Goddard Center
Author: Josefino C. Comiso
Where published: Journal of Climate

twenty-year record of space based measurements has been analyzed by researchers at NASA's Goddard Space Flight Center. Based on their findings, evidence of a warming planet continues to grow
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IPCC 2001 Report

Intergovernmental Panel on Climate Change

Emmissions of greenhouse gases and aerosols due to human activities continue to alter the atmosphere in ways that are expected to alter the climate
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