Dr. Ralph J. Cicerone
Field of reference: Ecology
Description: Studies about warming as presented to the US congress. Results: Earth is warming. Humans have impact on it.
"The Earth is warming. Weather station records and ship-based observations indicate that global mean surface air temperature increased about 0.7 degrees F (0.4 degrees C) since the early 1970’s. Although the magnitude of warming varies locally, the warming trend is spatially widespread and is consistent with an array of other evidence (melting glaciers, sea level rise, extended growing seasons, and changes in the geographical distributions of plant and animal species). The IPCC has estimated that, by 2100, global surface temperatures will be from 2.5 to 10.4 degrees F (1.4 to 5.8 degrees C) above 1990 levels." he ocean, which represents the largest reservoir of heat in the climate system, has warmed by about 0.12 degrees F (0.06 degrees C) averaged over the layer extending from the surface down to 750 feet, since 1993. Recent studies have shown that the observed heat storage in the oceans is consistent with expected impacts of a human-enhanced greenhouse effect. Increased ocean heat content accounts for most of the planetary energy imbalance (i.e., when the Earth absorbs more energy from the Sun than it emits back to space) simulated by climate models with mid-range climate sensitivity."
"Laboratory measurements of gases trapped in dated ice cores have shown that for hundreds of thousands of years, changes in temperature have closely tracked atmospheric carbon dioxide concentrations. Burning fossil fuel for energy, industrial processes, and transportation releases carbon dioxide to the atmosphere. Carbon dioxide in the atmosphere is now at its highest level in 400,000 years and continues to rise." "It is important to recognize, that while future climate change and its impacts are inherently uncertain, they are far from unknown. The combined effects of ice melting and sea water expansion from ocean warming will likely cause the global average sea-level to rise by between 0.1 and 0.9 meters between 1990 and 2100. In the Arctic regions, where temperatures have risen more than the global average, the landscape and ecosystems are being altered rapidly."
| שייך לנושאים: 1-13 - חינוך אינטגרלי, -מקורות מדעיים, משבר, 2. לראשונה גלובלי |
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