Climate Change Made Easy: It's the Sun

Bob Foster

For two decades now, 'the Great and the Good' have subjected us, the thinking public, to a blizzard of authoritative-sounding climate catastrophism. For instance:

• Most 20th Century warming was not, as in the past, the result of solar influences.
• Human-caused changes to the composition of the atmosphere now drive climate.
• Most 20th Century warming was (as will surely be the case in the new century) caused by anthropogenic greenhouse gas emissions, largely CO2 from burning fossil fuels.
• Global warming will harm us all---and the CO2 which causes it, is a pollutant.

British Prime Minister Tony Blair announced in Mozambique on 1 September 2002 (in support of the UN's World Summit on Sustainable Development in Johannesburg) that "we can defeat climate change if we want to". He meant that if we can curtail deeply enough our use of fossil fuels, we shall stop global warming. Of course, denying the citizens of the industrialized world the ready availability of low-cost energy will hurt jobs and living standards, and reduce their ability to buy goods from the impoverished Third World---who always suffer the most when times are tough. But this is a small price to pay for a stable climate, isn't it? Wrong!

Humans can't defeat climate-change. Continued change is inevitable; and, like it or not, the seas will rise and fall and extreme weather events will keep coming. Realistically, all we can do is to ensure that both human suffering and environmental degradation are minimized.

The Sun drives climate. This not-so-amazing fact is overlooked by the UN's Intergovernmental Panel on Climate Change (IPCC) and its numerical modellers. They may well accept that the Sun (in conjunction with its planetary system) drove past climate---but then it stopped. At about 1900, the Sun retired from the climate-change game; and natural climate 'stabilized'. Warming in the 20th Century was our fault. But there is worse to come. If we maintain our profligate ways, human-caused global warming of up to 5.8 ºC and sea level rise of up to 88 cm (i.e., between 1990 and 2100) will be the result. Frightening!

Earth has slipped into an Ice Age over the past several million years; and the main feature of our climate---cyclic at many time-scales---is an orbital/solar-related 100,000-year cycle of long Glacials and short Interglacials. Only 20,000 years ago, ice was piled upon Northern continents (1 km of ice over Detroit). Sea-level has risen 120 metres since then---during the transition to the Holocene Interglacial we now enjoy (warmer is better)---because warm water expands, although primarily because the ice sheets of the Northern Hemisphere have melted. At the human time-scale, our biggest ocean (the Pacific) has risen about 8 cm during the past century; and the rise appears not to be accelerating. Certainly, ice-streams from an ever-shrinking West Antarctic Ice Sheet continue flowing into the sea, as they have intermittently for millennia, but it isn't enough. Accepting an imminent ten-fold increase in the rate of sea-level rise is too big an ask.

In the Northern Hemisphere particularly, there is a (roughly) 1500-year solar-related warm/cold cycle right through the 10,000 years of the Holocene---of which the Roman Empire Warm Period, Dark Ages, Mediaeval Warm Period and Little Ice Age are the latest manifestations. Since the nadir of the Little Ice Age, the rebounding warm trend has been overprinted by a 50/70 year (again solar-related) cycle. The last cooling phase began in 1945, with renewed warming from the Great Pacific Climate Shift of 1976/77 (which remarkable event had an impact far beyond the Pacific). The two 20th Century warmings totalled about 0.6 ºC, with at least half the increase coming before WW2. In fact, much of the warming anticipated the sky-rocketting fossil-fuel use which was supposed to have been its cause!

Greenhouse is an atmospheric phenomenon; and IPCC got its 5.8 ºC projection by invoking a vast atmospheric CO2 increase to 2100. By assuming an almost-unimaginable rate of economic growth in the developing world over the century ahead, and by choosing to maximize the use of carbon-intensive coal in providing the energy needed to drive it, IPCC attained an atmospheric CO2 concentration of 970 ppm in 2100. It then added 30% for "uncertainties" and ran this monstrous outcome in the most CO2-sensitive of its seven climate models. The result: 5.8 ºC.

The underlying economic assumptions are inaccessible to the layman, because IPCC has divided the world only into four large economic units for the purposes of approval and publication. Hence, down-scaling to the level of the individual countries comprising these regions, although posted on a website, has no official standing. However, the regional totals are official; and if one component country were then to have its assumed future economic growth reduced, another would have to be increased in compensation. Subject to that caveat, per-capita GDP (expressed in thousands of 1990 US dollars) in the USA increases from 23 to 114 between 1990 and 2100. Equivalents for Australia and South Africa are 17 to 61 and 4 to 470, respectively. I did say "an almost-unimaginable rate of economic growth in the developing world", did I not?

That much-maligned gas, CO2, is a natural atmospheric constituent; and many extant plant families evolved when its concentration was 5 or more times that of today. Commercial growers enrich the atmosphere in their greenhouses by adding CO2---to make their plants grow better; and greening of the extra-tropical Northern Hemisphere over the 24 years of satellite observations attests to the broader-scale benefit of human-caused CO2 fertilization. In fact, without endemic 'pollution' of the atmosphere by this vital plant food, we would not be here.

Since the depths of the Little Ice Age (say 1700) and the start of the Industrial Revolution (say 1750), atmospheric CO2 concentration has risen from 280 to 370 ppm as a result of natural (physical and biological) and human (fuel burning and land-use change) influences. Oceans are a far larger CO2 reservoir than the atmosphere, and the rate of atmospheric increase jumped with the abrupt warming of the Eastern Pacific sea-surface---coinciding with the 1976/77 Shift---to a new average of 1.5 ppm/year. Apart from a dip after the Mt Pinatubo eruption and a spike with the Kalimantan peat fires, little has altered during the past quarter-century: there is no current acceleration in the rate of increase. But in order to achieve an implausible 1260 ppm by 2100, we need not 1.5 but 9 ppm every year---starting right now. Forget IPCC's 5.8 ºC.

Over the 100,000-year cycle, solar-system dynamics and continental ice-sheet movements have dominated climate; and even the intra-decadal El Niño/La Niña alternation looks solar-related. Acknowledging the Sun's dominant role in climate-change would open new lines of research---quite independent of IPCC's spurious economics, and the numerical models which feed off them. Behavior of the solar system may be complex, but it is certainly not chaotic. While seeming far-fetched to some, perhaps, useful projection of future climate may be possible after all.