• The average temperature of the earth has fluctuated during the past 100 years, sometimes cooling, sometimes warming, and in balance has increased somewhat, especially during the periods from 1910 to 1940 and from 1980 to 1998. Since 1998 there has been no further warming and apparently a slight cooling. There is a lot of controversy around the accuracy of these trends. In particular there is a concern that many of the weather stations used to determine the global average were originally in the countryside but over the years have been swallowed up by expanding urban development. The “urban heat island effect” refers to the fact that concrete and heat from buildings results in an increase in temperature in urban areas compared to the surrounding countryside,[20] thus the possibility exists that the results have been skewed.
In November 2009 the release of thousands of emails, leaked or hacked, from the Climatic Research Unit of the University of East Anglia in the U.K. shocked the climate change community. It was quite clear from a number of email exchanges that the scientists with this most important source of information had been manipulating data, withholding data, and conspiring to discredit other scientists who did not share their certainty that humans were the main cause of climate change. These revelations were quickly dubbed “Climategate” and have since been hotly debated in climate change circles.[21] [22] [23] It is very difficult to find a balanced account of this scandal. Commentary is divided sharply, with believers claiming that while the scientists involved behaved badly, this does not change the fact that the science is clear that humans are causing warming, while skeptics claim the revelations demonstrate the books have been cooked, placing the entire hypothesis of global warming in doubt.
In December 2009, after months of promotion and hype, the Copenhagen conference on climate change ended in disaster for the true believers. The delegates at the largest international meeting in history failed to reach a single binding decision to control CO2 emissions. There does not seem to be any conceivable strategy to achieve international agreement on this subject. The United States will not sign a deal that does not include China, India, Brazil, and the other developing countries. The developing countries will not agree to reduce or restrict their CO2 emissions so long as the U.S. and other industrialized countries have far higher emissions on a per capita basis. Whereas the U.S. emits nearly 20 tonnes (22 tons) of CO2 per person, China emits 4.6 tonnes (5.1 tons) and India emits 1.2 tonnes (1.3 tons). There is no possibility this impasse will be resolved in the near future. The U.S. will not agree to reduce its emissions to a lower level while the developing countries increase theirs. The developing countries will not agree to a system in which the U.S. and other industrialized countries are allowed even higher per capita emissions. Despite this obvious impasse, the delegates continue to meet regularly, thousands of people jetting to desirable locations like Bali, Montreal, and Rio de Janeiro at public expense, with no possibility of ever reaching agreement.
We can be fairly certain of the facts listed above, with the qualifications given. While this is very interesting, it is not the known facts but rather the unanswered questions that are most intriguing. Climate change cannot be defined by a single question. It is much like peeling back the layers of an onion, beginning with the science, leading to possible environmental impacts, followed by potential economic and social impacts, and concluding with policy options. Among these questions are:
• Is CO2, the main cause of global warming, either natural or human-caused?
• Are human-caused CO2 emissions the principle cause of recent global warming?
• Is the recent warming trend fundamentally different from previous warming and cooling trends?
• If warming continues at the rate experienced in the 20th century into the 21st century will this be positive or negative for human civilization and the environment?
• Is the melting of glaciers and polar ice really a threat to the future of human civilization?
• Will increased CO2 result in “acidification” of the oceans and kill all the coral reefs and shellfish?
• Is it possible for humans to halt global warming and to control the earth’s climate?
• Which would cost more to the economy, an 80 percent reduction in fossil fuel use or adaptation to a warmer world?
• Could the United States and China ever agree to a common policy on reducing CO2 emissions?
• Is the effort to conclude a binding agreement to control CO2 emissions among all nations futile?
These are just some of the many questions we must answer if we are to make intelligent choices about the direction public policy should take on the subject of climate change.
Before going into more detail I will clarify two key points. First, the fact that both CO2 and temperature are increasing at the same time does not prove one is causing the other. It may be that increased CO2 is causing some or most of the increased temperature. It may also be that increased temperature causes an increase in atmospheric CO2. Or it may be they are both caused by some other common factor, or it may be just coincidental they are both rising together and they have nothing to do with one another. Correlation does not prove causation. In order to demonstrate one thing causes another, we need among other things, to be able to replicate the same cause-effect sequence over and over again. This is not possible with the earth’s climate as we are not in control of all (or any of) the factors that might influence climate. Now, if we had a record of CO2 and temperature going back many millions of years and it showed that increased temperature always followed increased CO2, we would be a long way toward proving the point. As we shall see later, the historical record is not so clear on the relationship between CO2 and temperature.
Second, it is often assumed that the interests of humans and the interests of the environment are one and the same. This may be the case for some factors, such as rainfall, but for others it simply does not apply. Take sea level rise, for example. If the sea level rises relatively rapidly, it will damage a great deal of human infrastructure and a great deal of work and expense will be required either to protect or to replace farms, buildings, wharfs, roadways, etc. But fish and other marine creatures will be perfectly happy with the rising sea level and most land animals will not find it difficult to move a few feet higher. A 1.5 meter (5-foot rise) in sea level may inundate Bangladesh, turning much of it into a salt marsh and displacing millions of people. This would be devastating for humans, but from an environmental perspective there is nothing wrong with a salt marsh. From an ecological point of view, a natural salt marsh represents an improvement over intensive agriculture with monocultures of nonnative food crops. Fortunately, no credible scientist believes the sea level will rise anywhere near 1.5 meters in the next century.
A Longer View
Our lifetimes are so short compared to the billions of years of life’s history on earth that we tend to dwell on the very recent past when considering historical information. Nearly all the discussion of climate change is in the context of the past 100 years, or occasionally the past 1000 years, even though the earth’s climate has changed constantly for billions of years. Let’s take a look at the history of climate change in this larger context, in particular the past 500 million years since modern life forms evolved.
Temperature
The earth’s average temperature has fluctuated widely over the past one billion years (see Figure 1). It is interesting to note that during the Cambrian Period, when most of the modern life forms emerged, the climate was much warmer than it is today, averaging 25 degrees Celsius (77 degrees Fahrenheit). Only at three other times during the past billion years has the temperature been as cold as or colder than it is today. The age of the dinosaurs, the Jurassic and Cretaceous Periods, experienced a warm climate with a moderate cooling spell in the late Jurassic. Following the dinosaur extinction the climate remained warm for 10 million years, spiking to 27 degrees Celsius (80 degrees Fahrenheit), followed by a gradual decline that eventually led to the Pleistocene Ice Age. As the gra
ph below indicates, it is colder today than it has been throughout most of the past billion years.
Humans generally prefer warmer climates to colder ones. When I mention that the global climate was much warmer before this present Ice Age, people often say something like, “But humans were not even around five million years ago, certainly not 50 or 500 million years ago. We have not evolved in a warmer world and will not be able to cope with global warming.” The fact is we did evolve in a “warmer world.” The human species originated in the tropical regions of Africa, where it was warm even during past glaciations nearer the poles. Humans are a tropical species that has adapted to colder climates as a result of harnessing fire, making clothing, and building shelters. Before these advances occurred, humans could not live outside the tropics. It may come as a surprise to most that a naked human in the outdoors with no fire will die of hypothermia if the temperature goes below 21 degrees Celsius (70 degrees Fahrenheit). Yet as long as we have food, water, and shade we can survive in the hottest climates on earth without fire, clothing, or shelter.[24] The Australian Aborigines survived in temperatures of over 45 degrees Celsius (113 degrees Fahrenheit) without air conditioning for 50,000 years.
The fact that humans are essentially a tropical species explains why even today there are no permanent residents of Antarctica and only four million people living in the Arctic (0.06 percent of the global population). Most of the Arctic population is engaged in resource extraction and would not choose to live there otherwise. Historically, the very small populations of indigenous people in the Arctic managed to eke out a living by inhabiting ice-shelters, getting food from marine mammals and oil from marine mammals for heating and light. They used sled dogs for transport and protection from polar bears. There is a good reason why there are more than 18 million people in Sao Paulo, Brazil, only 4,429 residents in Barrow, Alaska,[25] and 3,451 inhabitants of Inuvik, Northwest Territory.[26]
Why are there 300 million people in the United States and only 30 million in Canada, which is larger geographically? One word answers this question: cold. About 80 percent of Canadians live within 100 miles of the U.S. border, as it is warmer there (although not by much in many regions) than it is in 90 percent of the country, which is frozen solid for six or more months of the year.
Figure 1. Graph showing global average temperature during the past billion years.[27]
So clearly, on the basis of temperature alone, it would be fine for humans if the entire earth were tropical and subtropical as it was for millions of years during the Greenhouse Ages. It would also be fine for the vast majority of species in the world today, most of which live in tropical and subtropical regions. But this would not be the case for some other species that have evolved specifically to be able to survive in cold climates.
The polar bear did not exist until the Pleistocene Ice Age froze the Arctic and created the conditions for adaptation to a world of ice. Polar bears are not really a distinct species; they are a variety of the European brown bear, known as the grizzly bear in North America. They are so closely related genetically that brown bears and polar bears can mate successfully and produce fertile offspring.[28] The white variety of the brown bear evolved as the ice advanced, the white color providing a good camouflage in the snow. Once bears could walk out to sea on the ice floes, it became feasible to hunt seals. It is possible that if the world warmed substantially over the next hundreds of years that the white variety of the brown bear would become reduced in numbers or even die out. This would simply be the reverse of what happened when the world became colder. Some varieties of life that exist today are only here because the world turned colder a few million years ago, following a warmer period that lasted for over 200 million years. If the climate were to return to a Greenhouse Age those varieties might not survive. Many more species would benefit from a warmer world, the human species among them.
The polar bear did not evolve as a separate variety of brown bear until about 150,000 years ago, during the glaciation previous to the most recent one.[29] [30] This is a very recent adaptation to an extreme climatic condition that caused much of the Arctic Ocean to freeze over for most of the past 2.5 million years. The polar bear did manage to survive through the interglacial period that preceded the one we are in now even though the earth’s average temperature was higher during that interglacial than it is today.[31] So as long as the temperature does not rise more than about 5 degrees Celsius (9 degrees Fahrenheit) above the present level, polar bears will likely survive. But that is a prediction, not a fact.
To listen to climate activists and the media, you would think the polar bear population is already in a steep decline. A little investigation reveals there are actually more polar bears today than there were just 30 years ago. Most subpopulations are either stable or growing. And the main cause of polar bear deaths today is legally sanctioned trophy hunting, not climate change. Of an estimated population of 20,000 to 25,000 bears, more than 700 are shot every year by trophy hunters and native Inuit. One hundred and nine are killed in the Baffin Bay region of Canada alone. And yet activist groups like the World Wildlife Fund use the polar bear as a poster child for global warming, incorrectly alleging that they are being wiped out by climate change.
The population of polar bears was estimated at 6000 in 1960. In 1973 an International Agreement between Canada, the United States, Norway, Russia, and Greenland ended unrestricted hunting and introduced quotas. Since then only native people have been allowed to hunt polar bears, although in Canada the native Inuit often act as guides for nonnative hunters. As a result of this restriction on hunting, the population has rebounded to its present level of 20,000 to 25,000. The International Union for the Conservation of Natural Resources Polar Bear Specialist Group reports that of 18 subpopulations of bears, two are increasing, five are stable, five are declining, while for six subpopulations, mainly those in Russia, there is insufficient data.[32] There is no reliable evidence that any bear populations are declining due to climate change and all such claims rely on speculation; they are predictions based on conjecture rather than actual scientific studies.
At the other end of the world in Antarctica, numerous species of penguins have evolved over the past 20 million years so that they can live in ice-bound environments. There are also many species of penguins that live in places where there is no ice, such as in Australia, South Africa, Tierra del Fuego, and the Galapagos Islands. It took 20 million years for the Antarctic ice sheet to grow to the extent it has been for the past 2.5 million years, during the Pleistocene Age. Antarctica differs significantly from the Arctic in that most of the ice is on land and at higher elevation. It is very unlikely Antarctica will become ice-free in the near future. It took millions of years for the present ice sheet to develop. In all likelihood the penguins will be able to breathe easily for thousands, possibly millions of years.
Coming closer to the present day, there is good historical evidence that it was warmer than it is today during the days of the Roman Empire 2000 years ago and during the Medieval Warming Period 1,000 years ago.[33] [34] We know that during the Medieval Warming Period, the Norse (Vikings) colonized Iceland, Greenland, and Newfoundland. The settlements in Newfoundland and Greenland were then abandoned during the Little Ice Age that lasted from about 1500 to the early 1800s.[35] The Thames River in England froze over regularly during the cold winters of the Little Ice Age. The Thames last froze over in 1814.[36] Since then the climate has been in a gradual warming trend. Given that there were very low levels of CO2 emissions from human activity in those times, it is not possible that humans caused the Medieval Warming Period or the Little Ice Age. Natural factors had to be instrumental in those changes in climate.
Speaking of natural factors, it is clear the climate changes over the past billions of years were not caused by our activities. So how credible is it to claim we have just recently become the main cause of climate change? It’s not as if the natural factors that have been causing the climate to change over the millennia
have suddenly disappeared and now we are the only significant agent of change. Clearly the natural factors are still at work, even if our population explosion and increasing CO2 emissions now play a role in climate change. So the real question is, are human impacts overwhelming the natural factors or are they only a minor player in the big picture? We do not know the definitive answer to that question.
Let’s go back to the IPCC’s Fourth Assessment Report in 2007, which stated: “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic (human-caused) greenhouse gas concentrations”[my emphasis]. The first word, most, in common usage means more than 50 percent and less than 100 percent, i.e., more than half but not all. That’s a pretty big spread, so clearly IPCC members don’t have a very precise estimate of how much of the warming they think we are causing. If they are that uncertain, how do they know it’s not 25 percent, or 5 percent? They restrict the human influence to “since the mid-20th century,” implying humans were not responsible for climate change until about 60 years ago. So the logical question is, What was responsible for the significant climate changes before 60 years ago, the warming between 1910 and 1940, for example? The most problematic term in their statement is “very likely,” which certainly provides no indication of scientific proof., The IPCC claims that “very likely” means “greater than 90 percent probability.”[37] But the figure 90 is not the result of any calculation or statistical analysis. The footnote entry for the term “very likely” explains, “in this Summary for Policymakers, the following terms have been used to indicate the assessed likelihood, using expert judgement, [my emphasis] of an outcome or a result: Virtually certain >
Confessions of a Greenpeace Dropout: The Making of a Sensible Environmentalist Page 48