Global temperatures in 2009 are continuing a nearly decade-long decline, with June readings from NASA satellites showing temperatures below 1980 levels.
NASA satellites first began measuring global temperatures in 1979. The readings are precise and not influenced by local land use changes and urban growth that corrupt data from ground-based temperature stations.
Carbon Dioxide Disconnect
Global temperatures have been falling since the end of 2001, defying alarmists’ assertions that carbon dioxide emissions are the primary driver of global temperatures. Global carbon dioxide emissions have continued rising since 2001.
Carbon dioxide is a greenhouse gas that warms the planet, but scientists disagree over whether it plays a major role in global temperature fluctuations.
All other things being equal, a full doubling of atmospheric carbon dioxide would raise global temperatures merely 1 degree Celsius, scientists report. Atmospheric carbon dioxide levels have risen by less than 50 percent since the dawn of the Industrial Revolution.
Alarmists theorize the small warming they say is caused by carbon dioxide emissions can trigger higher atmospheric relative humidity and more prevalent upper-level cirrus clouds, which would then bring substantial additional warming. Without that feedback effect, computer models predict little future warming.
National Oceanic and Atmospheric Administration measurements dating back several decades show there has been no increase in atmospheric relative humidity, even while atmospheric carbon dioxide has increased. Similarly, NASA instruments show there has been no increase in upper-level cirrus clouds in conjunction with the increase in atmospheric carbon dioxide. The positive feedback loops asserted by global warming alarmists have failed to materialize.
Solar and Ocean Cycles
Instead of behaving according to the alarmists’ feedback hypothesis, global temperatures have continued to follow closely fluctuations in solar output and ocean circulation cycles, not carbon dioxide trends. Solar output measurements by scientists at the Harvard-Smithsonian Center for Astrophysics show a near-perfect fit between twentieth century solar output and twentieth century temperature trends.
Solar output has declined this decade, again showing a strong correlation with global temperatures.
In addition, University of Alabama-Huntsville professor Dr. Roy Spencer, who oversees the NASA program that measures global temperature via satellite, has published data showing a very strong correlation between global temperatures and cyclical oscillations in Pacific and Atlantic Ocean currents. Whether solar activity plays a role in the Pacific and Atlantic Ocean current oscillations is still unknown.
Scientists Debunk CO2 Theory
William Gray, emeritus professor of atmospheric science at Colorado State University, noted, “Accurately modeling the global ocean’s deep circulation is fundamental to any realistic understanding of global temperature change. Such global deep-water circulation patterns are the primary control of global surface temperature. The global warming we have seen since the mid-1970s to 1999 and over the last 100 years is largely due to reductions in the rate of global ocean deep-water circulation—or Meridional Overturning Circulation—which has occurred. This circulation is driven by global ocean salinity variations. CO2 changes play no role in these ocean changes.”
Dr. Willie Soon, a researcher at the Harvard-Smithsonian Center for Astrophysics, agrees the contribution of CO2 is minute at most.
“Based on my research, I tend to support a very, very strong role by the sun as a climate driver. If you were to ask me about the role of CO2, I would say it’s very, very small,” said Soon.
James M. Taylor ([email protected]) is a senior fellow of The Heartland Institute and managing editor of Environment & Climate News.