Satellite temperature data indicate a general increase in global temperatures within the surface and troposphere, yet cooling is evident throughout the stratosphere.
Is this possible?
In short, these activities are suggesting that global warming is causing stratospheric cooling. Theoretically, are these climatic conditions controversial? Let’s excavate these phenomena further!
First, and according to geographers, the troposphere is the lowest level of Earth’s atmosphere with an average depth of approximately 11 miles in the middle latitudes. Furthermore, it is deeper in the tropics, runs up to 12 miles and shallower near the Polar Regions — about 4.3 miles. Within this portion is approximately 80 per cent of atmosphere mass and about 99 per cent of its water vapour and aerosols. The lowest portion of the troposphere — the planetary boundary layer, is where friction with Earth’s surface influences air, approximately a few hundred metres to 1.2 miles deep, relative to the landform and time of the day.
Similarly, the stratosphere is the second significant layer of Earth’s atmosphere and where the tropopause is formed, is a temperature inversion; stratified in temperature containing warmer layers higher up and cooler layers beneath — these are contrasting activities in the troposphere near to earth’s surface. At moderate latitude the stratosphere is situated between 6 to 8 miles altitude and 31 miles altitude above the surface; about 5 miles altitude at the poles and starts at 11 miles altitude at the equator.
Let us discuss the cooling of the stratosphere further!
Jeffery Masters, Ph.D., director of Meteorology, Weather Underground, Inc., stated that global temperatures during January to August 2011 were the third recorded coldest period in the lower stratosphere, which has been declining over time. The main reasons behind these activities are consequent to the destruction of the ozone layer created by human-emitted chlorofluorocarbon (CFC) gases.
Moreover, in the stratosphere the ozone absorbs solar UV radiation, which heats the air around it. However, loss of ozone means that less UV light is absorbed, which leads to cooling of the stratosphere. When the stratosphere cools it forms additional polar stratospheric clouds, which utilizes very cold temperature for formation. The drawback is that these cloud forms allow further deterioration of the ozone to occur considering that the reaction needed for ozone destruction occur rapidly in clouds compare to dry air. In retrospect, the recent cooling of the stratosphere enables high levels of harmful UV light to penetrate the surface. Subsequent to decline in CFC gases the stratosphere should start to warm, and the ozone levels recover.
Images recorded by the National Climatic Data Centre suggest global lower stratospheric departure of temperature from average dated back to 1979, measured by satellites. Additionally, the huge spikes in 1982 and 1991 are subsequent to the El Chicon and Mt Pinatubo eruptions, respectively. During that period these volcanoes ejected an astronomical volume of sulphuric acid dust into the stratosphere; dust that absorbed huge quantities of radiation; thus, heating the stratosphere.
However, those activities are not the only causes; there are more!
Greenhouse gases also cause stratospheric cooling –delaying the recovery of the ozone layer. A significant percentage of the observed stratospheric cooling is the result of human-emitted greenhouse gases, such as methane and carbon dioxide. Climatic models predict, however that compensation cooling must occur in the upper atmosphere considering the notion that greenhouse gases influence surface heating — this theory is evident on our sister planet Venus. Venus’ atmosphere is made up of 96.5 per cent carbon dioxide, which has sparked a run-way greenhouse gas effect of doubtless shocking proportions. Although the average surface temperature on Venus is a whopping 894 degrees Fahrenheit! In spite of this, Venus’ upper atmosphere is many times cooler when compare to Earth’s.
The idea behind this scientific conclusion is difficult, enormous and overwhelming; however, this is how it works — the amount of infrared heat energy radiated into space by a single planet is approximately equal to the volume of solar energy it assimilates from the sun. In so doing, if the surface atmosphere warms then there must be compensating cooling elsewhere in the atmosphere to equalize the amount of heat the planet releases. Hence, it is safe to say, that once emissions of greenhouse gases continue to rise, the cooling effect on the stratosphere will increase; slowing the recovery process of the ozone layer.
This is not all, scientists have, yet another stunning discovery!
Greenhouse gases also cause cooling higher up – leading to the cooling of the atmosphere at levels higher than the stratosphere. For three decades now, Earth’s temperature has risen 0.2 to 0.4 degrees Celsius. Meanwhile, the temperature in the mesosphere – the layer of the atmosphere 31 to 49 miles that is directly above the stratosphere and directly below the mesopause; where temperature decreases with increased altitude – has cooled between 5 to 10 degrees Celsius (Beig et al, 2006). At this altitude there is no appreciable cooling subsequent to ozone destruction, therefore, all this dramatic cooling is the result of greenhouse gases released into the atmosphere. To back this up, Lastovicka et al, 2006 indicated at 217 miles altitude greater cooling of 17 degrees Celsius every decade has been observed high into the ionosphere; a discovery that scientists claim has affected the orbits of orbiting satellites, because of decreased drag, relative to the shrink of the upper atmosphere, has caused it to move closer to the surface and creating a drop in the density of air between 2 to 3 per cent every decade for the last 30 years. In retrospect, the sky is falling!
For me, this is a difficult phenomenon to comprehend and discuss; referring to the cooling of the second significant layer of Earth’s atmosphere while the layer beneath is heating up. However, with real time evidence, research and discoveries one has to believe that these phenomena are true.
Until further research indicates differently, cooling of the stratosphere is real!
D. Markie Spring
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