The Past is the Key to the Present… and the Future


A Corollary of the Principle of Uniformitarianism

By Howard Dewhirst, Geologist

This document aims to contextualise the scientific debate concerning Climate Change (CC) and Anthropogenic Global Warming (AGW). Examining Earth history, it is indisputable that CC has been operating for many hundreds of millions of years, in cycles that span many different time-scales (millennial-plus to decadal), all without human influence. Understanding the causative factors in past CC provides a solid basis for framing the present debate. AGW is a notion which says that human activities, notably the addition of CO2 to the atmosphere, are causing an increase in the global heat budget. That higher-energy state of Earth’s environment it is argued sets the stage for damaging CC effects. Political and economic decisions have been influenced by this claim. Some of those decisions harm efforts to better the health and welfare of the world’s population, including both the poorest and those who are better off. If the CC and AGW arguments are incorrectly based, as we outline here, there is a need to re-consider those decisions.

CC in Earth History

  • Paleo-temperature (of atmosphere and ocean) is taken as a proxy indicator of climate, since climate is a complex concept that includes precipitation amounts and patterns, wind, etc whose history and future cannot be extracted or classified in a satisfactory way
  • Earth’s equatorial region has had a consistent temperature during the climate swings over hundreds of millions of years, but the polar areas have varied, thus altering the pole-to-equator gradient of heat energy, which is the principal driver of climate on the planet
  • Causes of CC (changes in temperature gradients) are dominated by orbital and solar effects, with added signals from volcanoes (both dust and chemicals), tectonics and plate motions, and biological feedbacks
  • Oceans (which cover ~70% of the planet) are the main heat reservoir, but with patterns of warmer and colder water distributions that reveal decadal and longer cyclicity that is not understood

Global Warming

    • Earth’s temperature has been generally rising since the end of the last ice age, with an apparent acceleration during the last century, but not since
    • Atmospheric concentrations of CO2 have also been rising more uniformly, now reaching 410ppm or 0.04% of atmosphere
    • CO2 has been identified as a ‘greenhouse gas’, based on an argument that it traps and reflects heat
    • The physics of CO2 heat retention are over-stated, as only a tiny portion of the electromagnetic spectrum (wavelengths of heat energies) can be captured by this molecule
    • Because CO2 concentration is rising and is implicated in global warming, and because CO2 is a by-product of combustion, energy sources from fossil fuels have been demonised – via social and political suppression of their use, and a push towards 100% renewable energy
    • There are three key challenges to the idea that CO2 is the primary cause of GW:
      •    Long-term records of CO2 and temperature show good correlation, but the CO2 concentrations lag behind temperature increases by thousands of years. Thus, CO2 increase is the consequence of rising ocean temperature, not the cause
      •    Numerical models of climate systems, which involve simplifying assumptions and methods that are associated with serious artefacts, consistently fail to ‘predict’ the known past temperature patterns. Such models cannot justify the suppression of hydrocarbon fuels.
      •    Average temperatures are no longer increasing despite the inexorable rise of CO2

Human activities are not the driver of global warming (or cooling). Earth’s systems are governed by processes that operate over a wide range of time- and length-scales, many of which far exceed the usual scope of human perceptions. The demonization of carbon is scientifically unjustified.

Howard Dewhirst

Read the open letter: https://carbon-sense.com/wp-content/uploads/2018/06/gsl-open-letter-dewhirst.pdf [PDF, 312 KB]

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