Climate Change News Summary
I’m going to summarize two global warming and climate change studies that were published today.
Ice cores reveal fluctuations in the Earth’s greenhouse gases
A core drilled through 3 kilometers of ice in the middle of Antarctica has returned CO2 (carbon dioxide), CH4 (methane) and O2 (oxygen) stretching back 800,000 years. Temperature curves (implied based on the ratio of O2 isotopes) mostly show a close correlation between the amount of CO2 in the atmosphere and the relative temperature.
â€œThe temperature curve over the past 800,000 years matches the CO2 curve beautifully â€“ during glacial periods in which the climate is cold, there is less CO2 in the atmosphere,â€ says Professor Thomas Blunier from the Centre for Ice and Climate at the Niels Bohr Institute, University of Copenhagen. He explains that when it is cold there is less plant growth, and so there are fewer plants to absorb the CO2 from the air, while more CO2 is absorbed in the oceans, so the final calculation is a low CO2 content in the atmosphere during glacial periods. This produces a lower greenhouse effect, and leads to an even colder climate.
However, the new results show that during the glacial period that occurred between 650,000 and 750,000 years ago, the CO2 level was extremely low â€“ lower than any previous measurements have indicated. It happened twice in this period, while the temperature was not lower than during other glacial periods.
Warming climate is changing life on global scale
A NASA study suggests that human induced climate change is impacting ecosystems and habitats at a large scale. The study looked at physical and biological impacts going back to 1970 and compared them to rising temperatures over that time frame.
Observed impacts included changes to physical systems, such as glaciers shrinking, permafrost melting, and lakes and rivers warming. Biological systems also were impacted in a variety of ways, such as leaves unfolding and flowers blooming earlier in the spring, birds arriving earlier during migration periods, and plant and animal species moving toward Earth’s poles and higher in elevation. In aquatic environments such as oceans, lakes, and rivers, plankton and fish are shifting from cold-adapted to warm-adapted communities.
The team conducted a “joint attribution” study. They showed that at the global scale, about 90 percent of observed changes in diverse physical and biological systems are consistent with warming. Other driving forces, such as land use change from forest to agriculture, were ruled out as having significant influence on the observed impacts.
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