Natural causes of climate change need to be acknowledged
While accepting that we humans are potentially causing damage to the earth’s atmosphere, we need to acknowledge that natural causes of climate change may also be at work here in order to maintain a balanced perspective.
Global warming proxies, or climate proxies, are being used to try to establish weather patterns in the past 2000 years based on such evidence as tree ring data, coral studies and ocean or lake sediments. While these types of data can provide clues, it is virtually impossible to state accurately whether climate change is man made or a natural recurring event over hundreds of years.
The temperature proxy data have been the most controversial because they are indirect, based on such things as sea sediments and stalagmites in caves, mostly in the Northern Hemisphere. There is simply no way to determine how accurate past temperature reconstructions based on proxies are. That would require many centuries of accurate thermometer measurements, and those do not exist.
Even if the proxies provided totally accurate temperature estimates, the low time resolution of the proxy estimates (thirty-year averages) must be considered before jumping to conclusions about record warm years. For instance, 1 998 is generally regarded as the warmest year for global average temperatures in at least the last 150 years. A few scientists have even proclaimed 1998 to be the warmest in the last 2,000 years, if not longer. But these statements are just meaningless, like comparing apples to oranges. The proxy data are not good enough to tell us just how warm individual years were, say, during the Medieval Warm Period. So, for example, there is no way to know how much warmer or cooler the year 855 A.D. was compared with the year 854 A.D.
If those individual years are embedded in a very warm thirty year period, it is entirely possible that one or more of them was considerably warmer than the “record” year of 1998. We had daily global measurements from multiple Earth-orbiting satellites in that year, and therefore we have a very good estimate of how much warmer 1998 was than 1997, probably to a precision approaching 0.01 deg. C. But there is no way to know with confidence whether 855 a.d. was warmer than 854 a.d. It is entirely reasonable to suppose – but impossible to prove – that one or more years in the Medieval Warm Period were warmer than 1998.
It is easy for scientists to make grand claims when there is no way to prove them wrong. In fact, the time scale of the temperature proxies for thirty years, is exactly the same as that used by the National Weather Service to determine climatological averages, or “normals.”
Despite what the United Nations’ IPCC would like you to believe, natural climate variability occurs on every time scale of any practical interest to humans: years, decades, centuries, millennia, and everything in between. Some of this variability is due to known cycles such as El Niño and La Niña.
What the “scientific consensus” has failed to account for is that global warming (or cooling) can happen through natural cloud changes altering the amount of sunlight being absorbed by the Earth. You wouldn’t think that a book on climate change would need to prove that natural climate variability exists. But one of the fundamental tenets of the current “scientific consensus” on global warming is that humans now control the future course of the global climate system.
The United Nations’ Intergovernmental Panel on Climate Change does acknowledge that there is natural climate variability on a year-to-year basis, and possibly also decade-to-decade. We already know that the weather events called El Niño and La Niña cause some years to be warmer than others. Yet the IPCC refuses to accept that global warming (or cooling) on time scales of thirty years or more can also be caused by Mother Nature. That, apparently, is humanity’s job. But, contrary to the claims of the IPCC, there is no basis for assuming that natural causes of climate change can’t occur on just about any time scale.
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