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Some perspectives on the science of climate change

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“Climate” is distinguished from “weather”, in that weather is the day-to-day state of the atmosphere and environment, whereas climate is the statistical average of weather patterns over a limited region and a long period (usually, minimum 30 years). A number factors have some influence on variations in the climate in the various regions or zones of the Earth – but it must be noted that none of these changes work (or actually initiate themselves) in isolation.

The natural climatic systems of the Earth are primarily determined by a dynamic complex of linkages, synergies and interactions among the processes, components and sub-systems of the atmosphere, hydrosphere, lithosphere and biosphere. The hydrosphere in this context includes all of the Earth’s water – oceans, rivers, lakes and the cryosphere (ice caps and snow). The main variables which characterize climate are temperature and precipitation (rainfall), humidity and cloudiness (special disturbances such as droughts and hurricances are sometimes included). These elements are in turn dependent on the meteorological variables (of weather) – such as insolation (solar radiation), wind speed and direction, ocean surface temperature, etc. To this must be added the variability of the Sun’s radiation and the Earth’s orbit, which result in an extremely complex and dynamic system.

Thus the climate system is a global complex of linkages and interactions. Inhomogeneities of all scales exist from the very large scale (e.g., 10,000 km) to the very small scale (e.g., 1 mm). This complex system is acted upon by a range of stimuli associated with the Sun, the Moon, and the Earth’s orbit around the sun. The main factors affecting climate change (natural variability) include: (1) Diurnal oscillations, due to the Earth’s rotation; (2) Tidal oscillations, due to gravitational effects of the Sun and Moon, with main periods of 12.4 hr and 24.8 hr; (3) Seasonal oscillations, due to the inclination of the equator to the ecliptic, and to changes in Sun-Earth distance; (4) Synoptic oscillations, caused by Rossby waves, with scales of 1000 km and periods of days; (5) Global oscillations with periods from weeks to months; (6) Inter-annual oscillations with periods ranging from 2 to 5 years, including El Niño/La Niña phenomena in the Pacific; and (7) Secular or long period oscillations with periods ranging from years to tens of thousands of years (the ice ages), likely due to orbital variations.

Having established the above – one of the main issues in the current debate is the possible effects of human industrial and other activities on the global climate. Despite the assertions in some quarters, anthropogenic effects are for the moment much smaller than these natural effects, the main concern being time-scales – their effects are felt within lifetimes rather than thousands of years. The critical point, is that many of the factors (“forcers” and “reactors”) in our current environment never existed in the past – many of the culprits (such as CFC) do not occur freely in nature, further to which, the rate of change of the release of naturally occurring greenhouse gases (such as carbon dioxide) over the past 200 yr or so (since the “industrial revolution”) is unprecedented and likely a result of human activities (such as deforestation). While, it is very true that global warming and climate change are a natural process on the Earth; the main issue is that the new or additional parameters added by human activities make it very difficult to use past cycles of “Ice Ages” and “Tropical Ages” to predict what is to be expected. Even if our activities are much less significant than natural variations (in the global context), they definitely are not helping the situation. Environmental changes by human activities also affect the micro-climate in which we live, on an obviously much shorter time-scale.

Recent discussions related to this post:

> http://geoenergy.wordpress.com/2008/07/05/some-perspectives-on-the-science-of-climate-change/

> http://www.geo-earth.com/forums/index.php?showtopic=7453

> http://discuss.greenoptions.com/viewtopic.php?f=31&t=531

> http://www.its2hot.in/viewtopic.php?f=27&t=96

> http://debateclimatechange.forumotion.com/science-of-climate-change-f1/some-perspectives-on-the-science-of-climate-change-t14.htm

> http://www.physicsforums.com/showthread.php?t=236709

> http://digg.com/environment/Some_perspectives_on_the_science_of_climate_change
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Further to what was previously discussed, it can be seen that the whole idea of the Earth’s “climate” is not as simple as it is made out to be in the media-hype (which in some form or the other has been ongoing for over 20 years). One important issue, is that the general discussion of climate variability seems to have become overly simplistic and narrowly obsessed with temperature and “global warming”. But the main point us that there is so much more to climate than temperature (which is no more than an index of the average internal energy of all the systems present at a given point of the globe). Why focus on factors related to temperature alone when the system is determined by many different factors in complex inter-relationship.

“Climate” can be easily defined – so it may be preferable to consider any form of climate variation from that perspective rather than singling out “global warming” or “sea level rise” which may have localized meaning, but general discussions are typically piecemeal (and far less, on an examination of relevance or utility of “data” to their given application).

It appears that much of the supposedly science-based discussion in the media (and adopted elsewhere) is oversimplified as though we were dealing with some highly-controlled environment, like in a laboratory thermodynamics experiment. Laboratory-based models (and their associated text-book theories) are meant to assist in understanding our environment (with a view to either adapting to, or “beneficially” modifying it) - but except in the case of very linear systems they are not intended to replace (or even become confused with) the structure, functioning and properties of the real-life system. So, one major point is that the oversimplification tends to lead to responses which are either too alarmist or overly defensive/dismissive.

When the whole idea of anthropogenic impact on climate was first taken up in the late 1980’s (by the glossy pop-culture news magazines of that era), the phenomenon was generally referred to as the “greenhouse effect” which in the context of the Earth’s atmosphere is an obvious over-simplification. I am sure that meteorologists and atmospheric physicists, who used that model to gain insight into the workings of the atmosphere, fully understood that the situation was very little like an actual greenhouse, but was just an analogy.

But the unfortunate reality is that when they put such a phrase into the public domain, the majority of people would think immediately of their own experiences with greenhouses. While the scientists may have been well-intentioned – what were the implications when pop-culture media took this up?

- Conditions outside greenhouse = before climate change;
- Conditions inside greenhouse = after climate change.

That was (I am pretty sure) never the intention of the terminology “greenhouse effect” in scientific text book theories, but it is just one example of the outcome of media-hyped oversimplification. It also immediately resulted in a narrow focus on the idea of Global Warming and starting from an over-simplified perspective, it then became entrenched in the minds of many people that the increases in CO2 emissions brought about by human activities would somehow be the same as putting thicker glass in your greenhouse. Further to which that the CO2 increases would somehow result in a linear heating correlation, without proper consideration of the dynamic complex of linkages, synergies and interactions among the processes, components and sub-systems of the atmosphere, hydrosphere, lithosphere and biosphere.

Needless to say, there are too many uncertainties remaining in the complex and poorly understood field of atmospheric dynamics as well as effects on the radiative equilibrium in terms of the entire solar spectrum and other factors (both internal to and external from, the Earth), for the broad declaration of “scientific concensus” and an end to all debate. But then again, was it a scientist who was the main promoter of that idea in recent years?

On the other hand, in sustainability science, there is the “precautionary principle” which states that if there are threats of serious irreversible environmental impact, lack of full scientific certainty will not be used as a reason for postponing measures to prevent environmental degradation. To what extent could (or should) that be applied to climate change, which in itself is a major aspect of the whole concept of “sustainability” (regardless of the definition in use)…
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workhard



Your perspective is ideal for professional studies in environment.


http://www.randygridley.com

basumayra0910



hi !!!


its really a informative post...


thanks for your information ...........

Environsave






hello guys ...
its really nice and informative post....
i just liked it....
thanks for your information guys ...........





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