Climate change first appeared on my radar in the early to mid-1980s. I spoke about global warming and the greenhouse effect with graduate students and at public health meetings from 1987 onward. I was invited to speak to ministers of health of Commonwealth nations at their biennial conference in Nicosia, Cyprus, in 1987. My first published paper on the implications of atmospheric changes for public health appeared in the Canadian Medical Association Journal in 1989. It attracted attention, and soon afterwards I was invited to write a comprehensive review for the trend-setting Annual Review of Public Health. In that review article I focused on two human-induced changes in the atmosphere, rising carbon dioxide concentration caused by combustion of carbon based fuels, and depletion of the ozone layer in the stratosphere caused by several ozone destroying substances such as freon.
The potential harm to all forms of life on earth from rising levels of ultraviolet radiation due to destruction or attenuation of the protective stratospheric ozone layer was readily recognized even by ultraconservative right-wing politicians like Margaret Thatcher, UK prime minister, and she, along with other world leaders, signed the Montreal Protocol (1987), aimed at restricting production and release into the atmosphere of ozone-destroying substances. The danger to all forms of life from exposure to high concentrations of UV radiation has been fended off, at any rate for the time being.
Reaction and responses to the equally grave threat to the stability of life-supporting ecosystems from global climate change has not been so unanimous nor as effective. Wealthy and powerful interest groups in the carbon fuel industries, i.e. oil and coal, and transport industries have fought determined rearguard actions to maintain the status quo. They have had support from many quarters, for example the Australian media mogul Rupert Murdoch, and several influential members of the US Congress. Several global conferences convened under the auspices of the United Nations have been little better than fiascos. So it is gratifying that all the world's nations gathered in Paris in early December 2015 achieved a rare show of unanimity in recognizing the gravity of the threat to global life-supporting ecosystems from rising atmospheric CO2 concentration and resolved to reduce, perhaps eventually to eliminate use of carbon-based fuels. It remains to be seen, of course, whether the resolutions voted into effect in Paris actually lead to effective action by all nations, especially China and India. These two large nations rely on large quantities of low grade coal to generate most of their energy. In China it powers the high speed rail network that the Chinese have built in recent years.
I summarized the impact of global warming on individual and population health most fully in a chapter in the 2nd edition of my book Public Health and Human Ecology (1997). The impacts are all adverse. Prolonged heat kills large numbers of people, an estimated 50,000 in the widespread European heatwave of 2003. Wendy and I were in Edinburgh when that heatwave began (I was there for the convocation where I received the honorary degree of Doctor of Medical Science). We stayed in the posh and prestigious North British Hotel, but it had no air conditioning, so it became very uncomfortable. It was even hotter in London, although at least the Domus Medica of the Royal Society of Medicine, my London 'Club', is air conditioned. But it was very oppressive out of doors. The Eurostar train that we took from London to Paris is air conditioned too, thank goodness, and so was our hotel in Paris, although inadequately. We sat a while in a park in the Marais, but abandoned our plans to stay a week in Paris to sample its many charms yet again. Instead we escaped after 2 days on the TGV to Geneva where the Cornavin Hotel, my favourite there, is air conditioned. But outdoor patios of restaurants aren't, so there too it was oppressively hot. It's easy to understand why so many died of heat stroke and heat exhaustion. Most were old and frail, or young and ailing. Wendy and I were in our late 70s then, and we found it hot enough to be distressing.
Since 2003, just as in the preceding 100 years, global average temperatures have continued to rise, in parallel with rising atmospheric concentrations of CO2. The rising global temperature has thawed polar and alpine ice-caps, exerting maximum effect at high latitudes: ambient temperatures have risen higher near the poles than anywhere else. I last flew over Greenland in August 2011 and saw for myself the dramatic impact of global warming on this large ice-covered island. It's no longer ice-covered, at any rate in late summer. Far below our plane as we flew over at 11,000 meters, we could see vast pools of melt-water everywhere; and the seas to the east and west of Greenland were dotted with innumerable icebergs, calved off the glaciers that run down to the fiords and drain into the sea along the coasts of Greenland. All that melting ice is coming from above sea level, so it is contributing to rising sea levels. So are even larger volumes of melt water from the land mass of Antarctica. The IPCC reports estimate that sea levels around the world will rise by at least a meter before 2100. In addition to rising concentrations of CO2 the atmosphere is being burdened by large quantities of methane, released from frozen bogs and from permafrost as this thaws. Methane is an even more powerful greenhouse gas than CO2, so it accelerates global warming. Most of the IPCC scientists say privately that the sea level will rise by much more than a meter, but even that modest rise will gravely threaten many small island states, e.g. the Maldives south of India, Kiribati and others in the Pacific, as well as low lying coastal regions of south China, Japan, India, Bangladesh, Holland, Miami and much of south Florida, the Mississippi delta, London and East Anglia and many other parts of the world. The habitat and food-growing regions of several hundred million people are at risk. Soon there will be many millions more environmental refugees.
I'll say more about the implications for food security, and about the direct and indirect impact of global warming on human health in another post.
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