How does rising atmospheric CO2 affect marine organisms?

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Volume 3 Number 12:  15 June 2000

The Global Surface Air Temperature Record May Be Significantly in Error: Several new analyses that have not appeared in the conventional peer-reviewed scientific literature provide convincing evidence that the global surface air temperature record that is used to justify Kyoto-style regulations of the fossil fuel industries is incorrect, and that rather than experiencing unprecedented warming over the last two decades, the earth has likely not warmed at all.

Journal Reviews
Recent Trends in Antarctic Surface Temperatures: Both surface station-derived and infrared satellite-derived surface air temperature data obtained over the continent of Antarctica indicate that the entire ice sheet has experienced a slight cooling over the past two decades.

Recent Trends in Antarctic Sea Ice Extent: A satellite-based study of Antarctic sea ice extent reveals that the mean edge of the ice surrounding the continent has been expanding equaterward over the past 18 years at an average rate of 0.011 degree of latitude per year.

Global Warming and Soil Moisture Trends: In a comparison of global climate model predictions vs. real-world observations of soil moisture response to increasing air temperature at a number of sites around the world, the authors of this study find that the hands-down undisputed winner is...

A Century of Storm Activity Along the U.S. East Coast: A study of 100 years of tide gauge readings obtained at ten locations along the east coast of the United States reveals no evidence of any change in storminess there over the past century of what has been called by many to be unprecedented global warming.

CO2, Vegetation and Climate: Learning from the Past: A study of the effects of changing air temperature and atmospheric CO2 concentration on earth's vegetation suggests that, as the climate continues to experience increases in temperature and CO2 concentration, there will be a decrease in the pole-to-equator temperature gradient, which should tend to reduce planetary storminess and extreme weather events.

Impacts of Land-Use Changes on Soil Carbon Sequestration: n a review of the scientific literature pertaining to land-use changes and soil carbon sequestration, the authors determined that rates of soil organic carbon accumulation are nearly identical for abandoned agricultural fields that have been reforested or converted into grasslands.  In addition, they determined that soil organic carbon contents could be increased by increasing soil organic matter inputs, placing those inputs deeper into the soil profile, and reducing the degree of soil tillage.  By using their calculated rates of soil organic carbon accumulation, the authors determined that only a small portion of the current Northern Hemispheric carbon sink is due to the storage of carbon in soils, and that the vast majority of this sink must exist within vegetative biomass and surface litter.

Modeling Ecosystem Carbon Sequestration in the United States as a Function of Increasing CO2 and Climate Change: Three ecosystem models that try to account for changes in climate and atmospheric CO2 concentration calculated an average terrestrial carbon sink in the United States of 0.08 Pg carbon per year for the period 1980-1993.  In addition, the authors determined that the bulk of this carbon sink resulted from the aerial fertilization effect brought about by increasing atmospheric CO2 concentrations.  Thus, as the CO2 content of the air rises, it is likely that the terrestrial carbon sink will increase.

Modeling the High-Latitude Terrestrial Carbon Sink: A hybrid vegetation model driven by climate change parameters, including atmospheric CO2 concentration, air temperature, and nitrogen deposition, predicted that forests in the Northern Hemisphere would increase their land coverage by about 50% between 1860 and 2100.  This expansion was determined to result primarily from the direct effects of rising CO2 concentrations on net primary productivity and biomass production.  As a result of this increased forest growth and expansion, a current annual carbon sink of 0.4 Pg of carbon was calculated for the Northern Hemisphere north of 50 N latitude.  In addition, this sink may increase to 1.0 Pg of carbon per year depending upon nitrogen deposition rates.  Thus, if these results hold true for forests in other regions of the world, it is conceivable that earth's trees may ultimately be able to remove all future anthropogenic emissions of carbon.

Effects of Elevated CO2 and Other Factors on Grassland Litter Decomposition: In a complex study designed to determine the effects of atmospheric CO2 enrichment on mixed-species litter decomposition, the authors determined that atmospheric CO2 concentrations during growth and decomposition had little if any impacts on decomposition rates, as did soil moisture and litter quality.  Nonetheless, mixed-species litter containing a high proportion of litter from nitrogen-fixing leguminous species contained greater initial litter nitrogen contents, and thus returned greater amounts of nitrogen to soils during decomposition.  Thus, if nitrogen-fixing species respond positively to increasing CO2 concentrations and increase their abundances in ecosystems, then vegetative productivity and growth in such ecosystems should be enhanced even more by rising CO2 levels due to greater nitrogen cycling and contents in their soils.

Effects of Elevated CO2, O3, and Moisture on Soil Microbial Biomass and Respiration: After growing wheat and soybeans in a crop rotation for two years, it was found that atmospheric CO2 enrichment significantly increased the size of easily mineralizable carbon pools in soils, while atmospheric O3 enrichment significantly decreased such pools.  In an elevated CO2 and O3 combination, however, the size of easily mineralizable carbon pools was not significantly different from that of such pools observed in ambient CO2 and O3 environments.  Thus, elevated CO2 tended to ameliorate the negative effects of high O3 concentrations on easily mineralizable carbon pools.  In addition, elevated CO2 significantly decreased soil microbial maintenance respiration rates and microbial biomass carbon losses, while elevated O3 significantly increased them.  In an elevated CO2 and O3 combination, however, elevated CO2 again tended to decrease the detrimental effects of elevated O3 on these parameters.