Can Natural Variation explain Climate Change? June 26, 2015Posted by wmmbb in CLIMATE CHANGE.
Climate for many of us is outside our preview. It is said that weather forecasts are accurate up to about five days. If you said to me that 1998 was a particularly hot year, I would have to say I did not notice at the time, and I cannot remember. Although, short of consulting with neighbours, I think it was around that time that one day the trains stopped, got on bus and drove through a flooded highway. I could be wrong.
Climate Change is caused. It is not limited to either temperature or precipitation, but involves other factors arising from a change in the energy balance in the troposphere and thus affects all forms of life on Earth. The climate system extends beyond the atmosphere, the importance of which is illustrated by comparison with, for example, the Moon or Venus. Without oxygen to breath most, if not all, land-based living forms would be dead within minutes.
Joseph Fourier, in part inspired by Issac Newton, emerging from his application of quantification and his theory of heat, had identified importance of the atmosphere. Fourier correctly identified there had to be something that trapped heat within the Earth’s atmosphere. Other components of the climate system include the Earth’s interior, thus vulcanization on land and under the oceans. Variation in it’s rotation and movement around the Sun.
Nineteenth Century scientists, principally Agassiz, at least identified the Ice Ages. In 1859, John Tyndall had gone further and identified the importance of water vapour and carbon dioxide. I suspect that both of these factors are related. Whether or not this might be then related to continental drift, I have no idea, but the fact that the Earth’s surface is about 70% water is a very significant factor. Of course nothing would happen in terms of the energy system without the irradiation of the sun, which for some reason the range of infrared radiation wavelengths are far wider than those associated with either visible light or ultraviolet radiation.
This is significant, I believe, in relation to Carbon Dioxide has a positive feedback relationship with water vapour, since warmer air can hold more water vapour. The ability to absorb infrared radiation photons by individual molecules, vibrate and then emit photons of infrared to return to the previous state, makes Carbon Dioxide, Water Vapour, Nitrous Oxide and Methane efficient Greenhouse gases.
Svante Arrhenius get into the act at the end of the century:
In 1896 Arrhenius completed a laborious numerical computation which suggested that cutting the amount of CO2 in the atmosphere by half could lower the temperature in Europe some 4-5°C (roughly 7-9°F) — that is, to an ice age level. But this idea could only answer the riddle of the ice ages if such large changes in atmospheric composition really were possible. For that question Arrhenius turned to a colleague, Arvid Högbom. It happened that Högbom had compiled estimates for how carbon dioxide cycles through natural geochemical processes, including emission from volcanoes, uptake by the oceans, and so forth. Along the way he had come up with a strange, almost incredible new idea.
It had occurred to Högbom to calculate the amounts of CO2 emitted by factories and other industrial sources. Surprisingly, he found that human activities were adding CO2 to the atmosphere at a rate roughly comparable to the natural geochemical processes that emitted or absorbed the gas. As another scientist would put it a decade later, we were “evaporating” our coal mines into the air. The added gas was not much compared with the volume of CO2 already in the atmosphere — the CO2 released from the burning of coal in the year 1896 would raise the level by scarcely a thousandth part. But the additions might matter if they continued long enough.(2) (By recent calculations, the total amount of carbon laid up in coal and other fossil deposits that humanity can readily get at and burn is some ten times greater than the total amount in the atmosphere.) So the next CO2 change might not be a cooling decrease, but an increase. Arrhenius made a calculation for doubling the CO2 in the atmosphere, and estimated it would raise the Earth’s temperature some 5-6°C (averaged over all zones of latitude).
The later calculation is the climate sensitivity of Carbon Dioxide. There is nothing new about the underlying science. Climate Science is natural science; it is necessary to observe what happens, in some cases what has happened, and take measurements.
Some scientists, in particular Judith Curry and Roy Spencer, to minimize the anthropogenic influence, wish to argue that Climate Change can be caused by natural variation, in the absence of obvious candidates such as land-based volcanic eruptions and changes in the Earth’s orbit. They suggest possible causes such as decadal changes in oceans flows such as the ENSO and cloud cover. Not that I can be sure, but these phenomena seem to be to derivative, as with temperature of the change in the Earth’s Energy Balance as well as related to changes in sea level and the cryosphere.
Long story short. Bloomberg Business has produced this neat set of graphic presentations. I am guessing 1.4 degrees Fahrenheit is about 0.63 degrees Celsius. Perhaps the insurance companies, unlike the fossil fuel emitters, have an interest in reducing Global Warming?
Richard Lindzen is extremely related about the possible human and other impacts of Climate Change. The discussion occurred before the Copenhagen Conference of Parties:
Apparently, the Pope takes his scientific advice from the Pontifical Academy of Sciences. One advisor, Peter Raven, is dismissive of climate change deniers, and is, what Richard Lindzen would call an alarmist:
“The climatic factors influencing the drought in California and in Sao Paulo are likely interconnected. Cycles in the Pacific sea surface temperature that occur on decadal timescales are coupled to changes in atmospheric circulation that affect weather patterns worldwide.
“In some regions, atmospheric conditions are such that they block the passage of cold fronts that cause the storms to bring precipitation, changing the path of these rain events.
“As long as these blocking conditions persist, there will be regions undergoing dry conditions, whereas others will be extremely wet. The North Pacific has been entering a phase that will likely increase the probability of these blocking mechanisms that favor dry conditions in California and other regions of the planet, including Sao Paulo.
“Of course, similar oceanic and atmospheric conditions have occurred in the past and will continue to occur in the future. The question that we should confront without hesitation is: how can global warming aggravate these extreme conditions, particularly in locations with high rates of urban growth such as Sao Paulo?
“And how fast should governments act and how much should be invested to mitigate these unprecedented conditions?”
– Leila Carvalho, Ecologist (Skeptical Science)