What is Climate Change? What Causes Global Warming?
The scientific community has warned that if greenhouse gas emissions keep increasing, the planet will reach a point of no return. Global. The president's climate change claims missed the mark. Donald Trump brought up a meme used often by those who deny climate change. and effect relationship between the greenhouse effect and the observed warming. In this way, CO2 may not be as potent a greenhouse gas as water a reliable correlation, no longer shows up in the global temperature That alone shoots down your whole false CO2 is the driver of warming meme. 2.
You are deluded by hubris — the idea that by reading one graph of suspect origin you know better than an entire scientific community consisting of literally thousands of researchers, operating over many decades and doing the actual hard work of science — and holding up their findings to rigorous review by expert peers.
I went on to say this: Their conclusions are nuanced — which is to be expected for a system as complex as global climate, and especially when looking at it over such long time periods. Other scientists have addressed particular details of the geologic record.
Yet climate dismissives do just that. The rise of the Appalachians plunged Earth into an ice age so severe that it drove nearly two-thirds of all living species extinct.
Commenters on my blog also often claim that since the concentration of CO2 in the atmosphere is so low compared to that of water vapor, also a greenhouse gas, it could not possibly play the role of a thermostat.
But here, too, rigorous research shows otherwise. The answer involves different characteristics of greenhouse gases. When the atmosphere cools enough, water vapor condenses and rains out. The researchers found that without these non-condensing greenhouse gases — CO2 foremost among them — there would be nothing to prevent the atmosphere from cooling enough to cause water vapor to rain out.
And since it is such a potent greenhouse gas, if water vapor were to rain out, the result would be very dramatic cooling. In this way, CO2 may not be as potent a greenhouse gas as water vapor, but it is actually more important. Researchers were using "climatic change" or "climate change" as far back as the early 20th century.
Also, polar ice is not increasing. President Donald Trump brought up a meme used often by those who deny climate change. I mean, look, it used to not be climate change, it used to be global warming. Researchers were using climatic change or climate change as far back as the early 20th century when writing about events such as ice ages.
Both terms can describe past, present, or future shifts—both natural and human-produced—on global, regional, or local scales. Courtesy SpringerLink, Springer Publishing By the s, scientists were becoming increasingly concerned about the threat of climate change arising from human-produced greenhouse gases.
15 quotes on climate change by world leaders | World Economic Forum
Global temperatures had been relatively flat since the s, and several intense cold waves and snowstorms in North America and Europe grabbed public attention in the s.
For example, in the mid 19th century, James Croll published calculations of how the gravitational pulls of the Sun, Moon, and planets subtly affect the Earth's motion and orientation. During some periods the Northern Hemisphere would get slightly less sunlight during the winter than it would get during other centuries.Greenhouse effect and global warming
Snow would accumulate, reflecting sunlight and leading to a self-sustaining ice age. InPeter Kropotkin wrote about his observations that since the Industrial Revolution, Siberian glaciers were melting.
Chamberlin By the late s, American scientist Samuel Pierpoint Langley had attempted to determine the surface temperature of the Moon by measuring infrared radiation leaving the Moon and reaching the Earth.
This result was unsurprising given that scientists had known about infrared radiation absorption for decades. InSwedish scientist, Svante Arrheniusused Langley's observations of increased infrared absorption where Moon rays pass through the atmosphere at a low angle, encountering more carbon dioxide CO2to estimate an atmospheric cooling effect from a future decrease of CO2.
He realized that the cooler atmosphere would hold less water vapor another greenhouse gas and calculated the additional cooling effect. He also realized the cooling would increase snow and ice cover at high latitudes, making the planet reflect more sunlight and thus further cool down, as James Croll had hypothesized.
Climate change, global warming and greenhouse gases | NIWA
Overall Arrhenius calculated that cutting CO2 in half would suffice to produce an ice age. He further calculated that a doubling of atmospheric CO2 would give a total warming of 5—6 degrees Celsius.
However, because of the relatively low rate of CO2 production inArrhenius thought the warming would take thousands of years, and he expected it would be beneficial to humanity. Previous advocacy of an atmospheric hypothesis, — The general doctrine that the glacial periods may have been due to a change in the atmospheric content of carbon dioxide is not new.
It was urged by Tyndall a half century ago and has been urged by others since. Recently it has been very effectively advocated by Dr. Arrhenius, who has taken a great step in advance of his predecessors in reducing his conclusions to definite quantitative terms deduced from observational data.
It follows that the effect of the carbon dioxide and water vapor is to blanket the earth with a thermally absorbent envelope.
An increase, by causing a larger absorption of the sun's radiant energy, raises the average temperature, while a reduction lowers it. The estimate of Dr. On the other hand, a reduction of the quantity of carbon dioxide in the atmosphere to an amount ranging from 55 to 62 per cent, of the present content, would reduce the average temperature 4 or 5 C, which would bring on a glaciation comparable to that of the Pleistocene period.
A second effect of increase and decrease in the amount of atmospheric carbon dioxide is the equalization, on the one hand, of surface temperatures, or their differentiation on the other. The temperature of the surface of the earth varies with latitude, altitude, the distribution of land and water, day and night, the seasons, and some other elements that may here be neglected. It is postulated that an increase in the thermal absorption of the atmosphere equalizes the temperature, and tends to eliminate the variations attendant on these contingencies.
Conversely, a reduction of thermal atmospheric absorption tends to intensify all of these variations. A secondary effect of intensification of differences of temperature is an increase of atmospheric movements in the effort to restore equilibrium. Increased atmospheric movements, which are necessarily convectional, carry the warmer air to the surface of the atmosphere, and facilitate the discharge of the heat and thus intensify the primary effect.
It now becomes necessary to assign agencies capable of removing carbon dioxide from the atmosphere at a rate sufficiently above the normal rate of supply, at certain times, to produce glaciation; and on the other hand, capable of restoring it to the atmosphere at certain other times in sufficient amounts to produce mild climates.
When the temperature is rising after a glacial episode, dissociation is promoted, and the ocean gives forth its carbon dioxide at an increased rate, and thereby assists in accelerating the amelioration of climate.
A study of the life of the geological periods seems to indicate that there were very notable fluctuations in the total mass of living matter. To be sure there was a reciprocal relation between the life of the land and that of the sea, so that when the latter was extended upon the continental platforms and greatly augmented, the former was contracted, but notwithstanding this it seems clear that the sum of life activity fluctuated notably during the ages.
It is believed that on the whole it was greatest at the periods of sea extension and mild climates, and least at the times of disruption and climatic intensification. This factor then acted antithetically to the carbonic acid freeing previously noted, and, so far as it went, tended to offset its effects.
Climate change, global warming and greenhouse gases
In periods of sea extension and of land reduction base-level periods in particularthe habitat of shallow water lime-secreting life is concurrently extended, giving to the agencies that set carbon dioxide free accelerated activity, which is further aided by the consequent rising temperature which reduces the absorptive power of the ocean and increases dissociation. At the same time, the area of the land being diminished, a low consumption of carbon dioxide both in original decomposition of the silicates and in the solution of the limestones and dolomites obtains.
Thus the reciprocating agencies again conjoin, but now to increase the carbon dioxide of the air. These are the great and essential factors. They are modified by several subordinate agencies already mentioned, but the quantitative effect of these is thought to be quite insufficient to prevent very notable fluctuations in the atmospheric constitution.
As a result, it is postulated that geological history has been accentuated by an alternation of climatic episodes embracing, on the one hand, periods of mild, equable, moist climate nearly uniform for the whole globe; and on the other, periods when there were extremes of aridity and precipitation, and of heat and cold; these last denoted by deposits of salt and gypsum, of subaerial conglomerates, of red sandstones and shales, of arkose deposits, and occasionally by glaciation in low latitudes.
Experimental attempts to measure infrared absorption in the laboratory seemed to show little differences resulted from increasing CO2 levels, and also found significant overlap between absorption by CO2 and absorption by water vapor, all of which suggested that increasing carbon dioxide emissions would have little climatic effect.
These early experiments were later found to be insufficiently accurate, given the instrumentation of the time. Many scientists also thought that the oceans would quickly absorb any excess carbon dioxide. The principal advances were in observational paleoclimatologyas scientists in various fields of geology worked out methods to reveal ancient climates. Bradley found that annual varves of clay laid down in lake beds showed climate cycles. An Arizona astronomer, Andrew Ellicott Douglasssaw strong indications of climate change in tree rings.
Noting that the rings were thinner in dry years, he reported climate effects from solar variations, particularly in connection with the 17th-century dearth of sunspots the Maunder Minimum noticed previously by William Herschel and others.
Other scientists, however, found good reason to doubt that tree rings could reveal anything beyond random regional variations.
The value of tree rings for climate study was not solidly established until the s.