By Dr D Weston Allen (MBBS, FRACGP) Aug 2019
Earth’s complex climate is always changing, sometimes rapidly. Greenland’s temperature rose ten degrees Celsius (10⁰C) in a single decade 11,500 years ago. Earth has been warmer than now and the atmospheric carbon dioxide (CO2) level much higher than now for most of its 4.5 billion years. Natural sequestration over 200 million years reduced it ten-fold from 2,000 parts per million (ppm) to just 200ppm 2.58 million years ago when Earth entered the cold Quaternary ice-age.
Milankovitch orbital cycles trigger interglacial warm periods such as our present Holocene. The Eemian interglacial was several degrees warmer than now. Warming oceans release CO2, helping plants thrive in a warmer and wetter world. Antarctic’s Vostok ice cores show CO2 levels rising with temperature and then falling as plants sequester it and Earth becomes colder, drier and dustier.
Civilisation began during the warm Holocene Climatic Optimum around 7,000 years ago, after which Earth began to slowly cool. Greenland’s ice-cores (GISP2) show the Minoan, Roman and Medieval warm periods interrupting this gradual cooling.
Europe flourished during the Medieval Warm Period (900-1300 AD) but was plagued by famine and disease during the subsequent Little Ice Age (LIA), especially during the Maunder Minimum of solar activity (1645-1715 AD) when rivers froze in winter and advancing glaciers wiped out alpine farms and villages. Cyclones were more severe in North Queensland during that cold preindustrial period. They are not increasing now.
Northern Victoria experienced a mega-drought during the LIA. The IPCC AR5 states: “There is low confidence in attributing changes in drought over global land areas since the mid-20th century to human influence.” Neither extreme weather events nor wildfires in the U.S. or globally are increasing in frequency or intensity.
The atmospheric CO2 level has increased by 46 percent (%) to 410ppm (0.041%) and the average surface temperature by about 1⁰C since the LIA. How much of that warming was due to fossil fuel emissions remains uncertain. Some scientists attribute 0.5⁰C or more to increased solar activity and others attribute 0.27⁰C to altered land use and increasing urban heat.
Fluctuations in atmospheric CO2 follow changes in sea surface temperature, so the relationship is complex. It is also logarithmic, which means that every doubling of the CO2 level produces the same temperature effect (about 1⁰C without feedbacks) because its main infra-red absorption band (15µm wavelength) is saturated. Further absorption of outgoing radiation occurs only at the edges of that band – blue arrows in following figure.
Greenhouse warming is mainly at night, increasing the minimum rather than maximum temperatures.
It thereby reduces temperature variability and the diurnal temperature range, and this is associated with reduced mortality and morbidity, particularly from cardiovascular and respiratory diseases. Urban heat increases both minimums and maximums, intensifying heatwaves in cities, which can be over ten degrees hotter than the surrounding countryside. Exposure to cold nevertheless kills twenty times more people than heat exposure globally. Cold weather is likely to remain more lethal than heat in most regions this century, even without mitigation or adaptation to climate change.
The increase in the average global surface temperature long after the CO2 level has doubled and stabilised is called the equilibrium climate sensitivity. The latest scientific report of the Intergovernmental Panel on Climate Change (IPCC) says it is “likely between 1.5⁰C and 4.5⁰C” – it’s that uncertain! And recent studies indicate that it is most likely near the lower end of that range. Warming this century is therefore likely to be modest. There is no scientific consensus on dangerous warming. Catastrophic predictions are based on climate models but they greatly overestimate recent warming.
Climate model projections (grey band) and their average (solid black line) with three satellite-based temperature records (coloured lines). Source: Real Climate
Since the car replaced the horse in the U.S., there are more trees and they are growing faster. By stimulating plant growth and improving their water use efficiency, CO2 emissions have been greening the planet.
Human emissions have also increased food production globally by at least 15%. Future food security depends on them. Horticulturalists greatly boost production with CO2 at up to 1,300ppm in their greenhouses.
By lifting living standards, mechanising agriculture and food distribution, fossil fuels help reduce global famine, infant mortality and birth rates, and increase longevity.
Global warming is not accelerating. Polar bears are thriving and Walruses are not falling off cliffs due to climate change. Anyone worried about extinctions due to climate change should read Landscapes and Cycles. The Great Barrier Reef is recovering from (exaggerated) bleaching during the 2016 El Nino. It can exist only during warm interglacial periods when the Pacific Ocean rises 120 metres or more.
Tide gauges around Australia show a steady rise of around 1.7mm a year (17cm per century) with minimal acceleration. Global warming makes more sub-Arctic land habitable and productive, compensating for low-lying land lost to sea level rise. Some need not be: 27% of the Netherlands is below sea level.
Rather than rushing to remedy a contrived emergency, we need to carefully consider the costs and benefits of climate mitigation, keeping in mind that nearly six million of the world’s poorest people die every year from burning wood, dung, crop waste and charcoal.
The IPCC 2018 Special Report proposed converting six million square kilometres (about 12%) of Earth’s agricultural and pastural land to growing energy crops instead of food, but turning corn into biofuel only increases emissions and food costs. Making biodiesel from palm oil, and burning wood pellets instead of coal – both promoted in Europe after Kyoto – only increase deforestation, energy insecurity, emissions and real air pollution. Every year, wind farms kill millions of bats and birds, including endangered raptors.
Renewables are very resource hungry. The mining and refining of rare earths for wind turbines and electric vehicles (EVs) is polluting Inner Mongolia with large quantities of radioactive waste. Mining the lithium and cobalt for Lithium-ion batteries poses environmental and humanitarian concerns. EVs are 25% heavier than their equivalents, about 70% more energy intensive to manufacture, and every metric ton of carbon saved during use costs around US$980! The photovoltaic (PV) solar industry is a leading emitter of potent greenhouse gases. The short life expectancy of solar panels poses a waste disposal problem.
Nature pays a heavy price for vast arrays of panels, fields of turbines and monoculture energy crops. This coal-fired power station produces 17.6 times more energy day and night than this PV solar farm, Australia’s largest, in full sunlight. The overall environmental cost per unit of energy produced is greater for renewables than for fossil fuels.
The social cost of carbon is nebulous as shown here. Australia produces just over one percent of global emissions, and our per capita emissions are falling while China’s are rapidly rising. Halving ours would greatly impact our economy but make no measurable impact on climate.
The CSIRO recently published its Australian National Outlook 2019, an ambitious and optimistic vision for net-zero emissions by 2050. It proposes increasing the density of major cities by 60-88% and EVs to 80%, achieving 95% renewable electricity (5% gas), allocating 30 million hectares to plantings for carbon credits, and over two million hectares for wind and solar farms. Thanks to taxpayer and user subsidies, these now provide about 14% of our electricity. Wind power is unviable in the U.S. without subsidies. Remote sources can also have a transmission loss of 10-22%.
The expensive infrastructure required to maintain supply using intermittent sources greatly increases the cost of electricity. South Australia has about 50% renewables and the highest power prices in the world. When the wind stops, its wholesale price of $98/MWh spikes to $14,500/MWh. After a long state-wide blackout, SA installed the world’s largest battery, a $90 million 100-megawatt Tesla capable of storing as much power as the state uses in 5-10 minutes. Using the batteries in electric vehicles would mean charging them by day (while at work) and feeding the grid by night using expensive infrastructure. To achieve zero transport emissions by 2050 would require 3-4 times the world’s lithium and cobalt reserves unless recycling becomes feasible. The lithium price is already soaring.
Pumped hydro has a lower energy efficiency than batteries and is vulnerable to drought. Snowy 2.0 could provide one week of storage at 2,000 megawatts for twice the cost of an equivalent coal-fired power plant.
The vagaries of wind and weather render renewables unreliable or unaffordable, pushing industry, jobs and emissions offshore. Building a strong economy requires reliable energy using high efficiency low emissions (HELE) coal-fired power plants or cleaner and more efficient combined-cycle gas-fired plants or zero-emissions Allam Cycle plants.
The safest energy source with the smallest footprint and lowest lifetime emissions is nuclear power. France has half Germany‘s emissions per capita and much cheaper electricity using over 70% nuclear. The U.S. produces nearly a third of the world’s nuclear power with far fewer deaths per unit of energy produced than with renewables.
Advanced nuclear power plants are even safer, smaller, cheaper and faster to build, more efficient, produce less waste, compete economically with unsubsidised renewables, have two to three times the lifespan, are better for the environment and more sustainable.
Australia is geologically stable, has the world’s largest uranium reserves, the best technology for enriching it and space to store radioactive waste. EVs make most sense in cities supplied by either nuclear power (e.g. France) or hydropower (e.g. Norway).
While development banks have scaled back or halted investment in coal-based energy projects, China is building hundreds of new plants to assist developing nations climb the traditional energy ladder. Their rapidly changing status may look very different in 2050.
In conclusion, misguided mitigation could do more damage to the global environment and economy, and impact the poor more than climate change itself.
About the Author: Dr Allen is a GP in northern NSW, a member of The Saltbush Club and the CO2 Coalition. He has published papers in the Medical Journal of Australia and Australian Family Physician, letters in The Lancet, and has critiqued publications on both sides of the climate debate, including The Weather Makers and Slaying the Sky Dragon. He produced a White Paper on Climate Change and Health for the CO2 Coalition. He has both PV solar and solar HWS on his home and no vested interests in any energy-related companies. He cycles to work and elsewhere but has no illusions about saving the planet with a low carbon footprint.
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