Καράντη Μαρία (cross) έγραψε:
Με την παρατηρούμενη αύξηση στα ατμοσφαιρικά επίπεδα διοξειδίου του άνθρακα (CO2) στον Πλανήτη μας, από το έτος 1750 μέχρι σήμερα, η συνεπαγόμενη αύξηση της υπέρυθρης ακτινοβόλησης κοντά στην επιφάνεια της Γης ανήλθε σε μονάχα 1.82 ± 0.19 W m−2!
Δε φτάνει για να αιτιολογήσει αύξηση θερμοκρασίας.
Πολύ περισσότερο συνεισφέρουν οι υδρατμοί στα σύννεφα.
www.nature.com/articles/nature14240
Πουλητάρια σε ... σκόπιμη και ... μόνιμη σύγχυση ....
Scientists have beaten down the best climate denial argument.
www.theguardian.com/environment/climate-...mate-denial-argument
skepticalscience.com/clouds-negative-feedback.htm
www.scientificamerican.com/article/7-ans...contrarian-nonsense/
Claim 1: Anthropogenic carbon dioxide can't be changing climate, because CO2 is only a trace gas in the atmosphere and the amount produced by humans is dwarfed by the amount from volcanoes and other natural sources. Water vapor is by far the most important greenhouse gas, so changes in CO2 are irrelevant.
Although CO2 makes up only 0.04 percent of the atmosphere, that small number says nothing about its significance in climate dynamics. Even at that low concentration, CO2 absorbs infrared radiation and acts as a greenhouse gas, as physicist John Tyndall demonstrated in 1859. Chemist Svante Arrhenius went further in 1896 by estimating the impact of CO2 on the climate; after painstaking hand calculations, he concluded that doubling its concentration might cause almost six degrees Celsius of warming—an answer not much out of line with recent, far more rigorous computations.
Contrary to the contrarians, human activity is by far the largest contributor to the observed increase in atmospheric CO2. According to the Global Carbon Project, anthropogenic CO2 amounts to about 35 billion tons annually—more than 130 times as much as volcanoes produce. True, 95 percent of the releases of CO2 to the atmosphere are natural, but natural processes such as plant growth and absorption into the oceans pull the gas back out of the atmosphere and almost precisely offset them, leaving the human additions as a net surplus. Moreover, several sets of experimental measurements, including analyses of the shifting ratio of carbon isotopes in the air, further confirm that fossil-fuel burning and deforestation are the primary reasons that CO2 levels have risen 40 percent since 1832, from 284 parts per million (ppm) to more than 400 ppm—a remarkable jump to the highest levels seen in millions of years.
Contrarians frequently object that water vapor, not CO2, is the most abundant and powerful greenhouse gas; they insist that climate scientists routinely leave it out of their models. The latter is simply untrue: from Arrhenius on, climatologists have incorporated water vapor into their models. In fact, water vapor is why rising CO2 has such a big effect on climate. CO2 absorbs some wavelengths of infrared that water does not, so it independently adds heat to the atmosphere. As the temperature rises, more water vapor enters the atmosphere and multiplies CO2's greenhouse effect; the Intergovernmental Panel on Climate Change notes that water vapor may “approximately double the increase in the greenhouse effect due to the added CO2 alone.”
Nevertheless, within this dynamic, the CO2 remains the main driver (what climatologists call a “forcing”) of the greenhouse effect. As NASA climatologist Gavin Schmidt has explained, water vapor enters and leaves the atmosphere much more quickly than CO2 and tends to preserve a fairly constant level of relative humidity, which caps off its greenhouse effect. Climatologists therefore categorize water vapor as a feedback rather than a forcing factor. (Contrarians who don't see water vapor in climate models are looking for it in the wrong place.).
Because of CO2's inescapable greenhouse effect, contrarians holding out for a natural explanation for current global warming need to explain why, in their scenarios, CO2 is not compounding the problem.