A brief history: the case for adaptation to global warming

Dr. John Hollins, past Chair CACOR Board of Directors presents “The case for adaptation to global warming”

The phenomenon of global warming and cooling by the constituents of the atmosphere has been understood to a substantial degree for almost two centuries.

In 1824, the French scientist Joseph Fourier postulated that Earth’s atmosphere kept the planet warmer than would be the case if there were no atmosphere.  He knew that visible light from the sun passed readily through the atmosphere and warmed the surface of the Earth, which then emitted infrared light back towards space.  Fourier also knew that the atmosphere did not transmit infrared as efficiently, so the surface temperature could increase, but he did not know by how much.

Towards the end of the 19^th Century, Swedish scientist Svante Arrhenius measured for the first time the absorption spectrum of carbon dioxide (CO₂).   He was aware of the findings of American scientist Samuel Langley, who had shown that the absorption by Earth’s atmosphere of infrared light from the Moon was greater at low angles, where it encountered more CO₂ than at high angles.

Arrhenius calculated that cutting CO₂ in half would suffice to produce an ice age. He further calculated that a doubling of atmospheric CO₂ would give a total warming of 5–6 degrees Celsius.  Subsequent analysis shows that Arrhenius was substantially correct; first approximations in physics are often all one needs to understand and address a phenomenon[i].

It took until the 1980s for a larger part of humankind to come to a broad understanding of the causes and dangers of global warming.  Of signal importance was the 1988 Toronto Conference on the Changing Atmosphere, hosted by Prime Minister Brian Mulroney and the Government of Canada.  Scientists, activists, and politicians from many countries thoroughly grasped the problem and understood technically what it would take to solve it.  What we have learned since is that the vested short-term interests of too many electors and politicians overwhelm the ability of most democratic governments to effectively address this long-term issue, to this day.  And dictators and oligarchs do not care, even if they understand.

The globe has already warmed by 1ºC since the nineteenth century, and northern Canada by 2.5ºC.  Dispassionate prognosis, for example, by the Harvard Project on Climate Agreements, suggests that under the Paris Agreement there is a 50% probability of warming being limited to 2.7º; and a 50% probability of warming going above 2.7ºC, even if all the commitments are met.  Compare that with the Paris target of 2ºC and the politically popular illusion of 1.5ºC!

Global warming caused by humankind has indeed arrived and the picayune efforts to moderate it to date are likely to remain largely ineffective. It may take one or more substantial catastrophes to secure action commensurate with the issue, by which time it may be too late.

The primary task for Canadians therefore should be timely preparation to adapt to what we can anticipate will happen at home and the consequences of much larger effects in other places.

It is past time for Canada to put at least as much effort into adaptation as into mitigation of emissions.  Mitigation has an effect on the scale of the globe, whereas adaptation is essentially local. Investors in adaptation are more obviously beneficiaries than investors in mitigation, where benefits may be greater in faraway places.  Adaptation is the issue now and a persuasive case could be made.

For government and business, adaptation is just sane, knowledgeable risk management, consistent with modern practice. Furthermore, as soon as enough Canadians grasp the case for serious and substantial attention to adaptation to inevitable change, that would become a driver for mitigation.

[i] We now know that the surface of the Moon, which receives the same flux of solar radiation as the Earth but has no atmosphere, is -23°C, about 37°C cooler than the Earth.