November 2006 ISSUE
Readers’ Forum
Hockey Stick Curve, Other Data
Thoroughly Verified
We welcome Readers’ Forum letters of interest to the professions. Send them to George Lee, glee@apega.ca. Keep them to 300 words or less. Letters represent the opinions and not necessarily the expertise of writers. The PEGG reserves the right to edit or reject any letter.
Within the scientific community there is little doubt the Earth’s climate has warmed since the onset of the industrial revolution and warming has accelerated over the last 50 years. The Earth’s temperature record over the last few 1,000 years, the famous hockey stick curve of Mann et al., has been substantiated by two independent studies using different data sets.
This has also been verified by the National Academy of Science in the U.S., in an exhaustive review of all direct and proxy temperature data. Members of the academy conclude that the last few decades of the 20th century are the warmest over the last 400 years, and that recent warming is unprecedented over the last 1,000 years and likely over the last 2,000 years.
There is little doubt within the atmospheric science community that the cause for much of the warming, particularly since 1976, is anthropogenic greenhouse gases. The natural causes called orbital variation and tectonism operate over much longer time spans than recent warming. Volcanic eruptions are readily apparent on the climate record as short-term cooling due to dust emission.
Solar output, measured directly since the 1950s, has varied by less than one per cent (during the period of greatest warming). Solar variations prior to that can be inferred by sunspot activity, which indicates more substantial changes.
The magnitude and pattern of warming are consistent with enhanced greenhouse effect. Replication of the Earth’s climate over the last 100 years, using known magnitudes of the various drivers, requires summation of solar variability, volcanic emissions and anthropogenic greenhouse gases.
The warming over the last 40 years can only be explained by enhanced greenhouse effect due to human activity. Andrew J. Weaver says in Hard Choices (2004), “In fact there does not appear to be any detection or attribution study done that has been able to explain the warming in the second half of the century through any known natural causes.” The warming during the early 1900s is attributed to increased solar output, while the mid-century cooling is attributed to soot and ash in the atmosphere due to the burning of coal.
Opposition to the science of climate change is not directed towards changing the science (rarely do climate change sceptics publish refereed articles in scientific journals). Rather, it is directed at influencing public opinion and political decision making.
The aim of climate change sceptics is not at truth; rather it is at power, specifically to preserve the power of those segments of our society that view climate change as a threat to profits.
Canada’s position on climate change is analogous to one who dines at a sumptuous banquet and then, when the bill arrives, refuses to pay. We are an immensely rich nation; to argue that we cannot afford to pay is ludicrous in the extreme.
The cost to Canada for meeting our obligation to the Kyoto Protocol is estimated to be from 0.5 to 3 per cent of GDP growth, says Hard Choices. Although the protocol may not be perfect, it represents a remarkable diplomatic achievement. It can also be modified in the future to be more inclusive and more effective.
The costs for not addressing climate change are staggering. Complete melting of the polar ice cap in the summer, by mid-century, will result in elimination of the Arctic ecosystem. Polar bear birth rates are already declining and Melville Island caribou are dying of hypothermia and exhaustion after falling through thin ice during their autumn migration.
The Inuit will lose their cultural identity. Sea level rise, over the next century, is estimated to be from 0.5 to two metres. This amount of rise will flood much of Holland, Bangladesh and low lying coastal cities. Holland has already budgeted 40 billion dollars to strengthen its system of dykes.
With the flood of fresh water entering the North Atlantic due to melting of the Arctic ice cap and Greenland ice sheet, the Gulf Stream could shut down as it has in the past, dramatically altering the climate of north-western Europe.
By meeting the climate change challenge head on, Canada could become a leader in new technology and processes for reducing emissions. Alberta in particular could become the leader in sequestration of carbon dioxide, while simultaneously enhancing our oil output.
The Sept. 9 edition of The Economist, not known for alarmist reporting, contains an excellent summation of the state of knowledge regarding climate change.
J. Edward Mathison, P.Geol.
Calgary