If you’d asked me, right up until a short time ago, about Global Warming, I’d have said that it was a well-established scientific fact, with the only scientific debate being how much of it was caused by the natural variability of the earth’s climate and how much was due to man’s industrial contributions.
So far, so good.
If pressed, I would probably have said that it would not be too long before it started to affect living things and that, if something weren’t done about it, within the lifetimes of our children or perhaps our grandchildren, it would become a significant problem.
Boy! Was I wrong.
Turns out I was behind on my data. A little investigation showed that, in the science community at any rate, it is acknowledged as a serious problem already. That some species have already been driven to extinction by it. That we are already long past the point where we should have been doing something about it. And that to save the world we know, it might already be too late.
But let’s begin at the beginning.
Imagine that you hold a globe that is eighteen inches across. Now visualize our atmosphere, which is something like 90 miles thick (not counting the exosphere which, as its name implies, is ouside the planetary sphere – the air is so thin that satellites orbit there) covering that globe. Odds are, your mental picture has the atmosphere way too thick.
The truth is, on a scale where the globe is eighteen inches across, our gaseous layer would be about one sixteenth of an inch thick – about the diameter of an old-fashioned pencil lead. In other words, the envelope that sustains and protects us is actually a thin, fragile film. To really appreciate the changes that have occurred over the last fifty years or so, you have to keep that image in mind.
There are several more facts to keep in mind. One is that, while in the atmosphere the amount of many of the greenhouse gases (i.e. those that tend to absorb and retain heat from the sun) are rising, CO2 has been going up by far the fastest. CO2 is a relatively rare gas in the atmosphere – up to 1800 it was a fairly stable 280 parts per million. By 1900 it was about 300 ppm. Today it is about 380 ppm or about 36% higher than before the Industrial Revolution. Which is, at least, one heck of a percentage change.
And just to keep things in perspective, that tiny figure of 380 ppm still amounts to around 869 gigatons of carbon floating around. It is arguable, of course, that some natural phenomenon has led to a release of part of the earth’s enormous reserve of carbon, thus causing the rise. However, it is at least curious that the rate of rise exactly matches the rate of increase of human CO2 production and that the change in the total amount rather precisely matches the human contribution.
Another fact to keep in mind is that CO2 has a life span in the atmosphere of roughly fifty years. Which is another way of saying that we are going to be living with the CO2 we have already made and are making today for a very long time. And since the usage curve is still upward, any changes we make are going to take a long time to bring the CO2 concentration to a stable level.
Last fact to keep in mind is that although we like to speak of all the human contributions to these problems as being a result of pollution, CO2 is rather a special case. Unlike oxides of nitrogen, harmful particulates, and the like, CO2 is not a product of incomplete combustion or of contaminates in the fuel. CO2 is the natural product of any combustion of a carbon based fuel, whether it is wood, coal, oil, natural gas, ethanol, or what have you. While it is certainly true that some fuels and some forms of combustion are more efficient than others (for instance, burning anthracite coal to produce electricity produces, at best, 67% more CO2 than does burning methane), they all produce CO2.
Okay. So there are more greenhouse gases in the atmosphere, especially CO2. And okay, so maybe we have experienced a tiny rise in average temperature (a “whopping” 1.13E F). So what?
This is what: the world has begun to change around us in some fairly major ways and we simply haven’t noticed.
1) Species have already begun to move. Since 1950 plants and animal species have been migrating towards the poles at a rate of about 4 miles per decade. And those are average numbers. Some butterflies have move poleward 150 miles. They have also begun to move up the mountainsides at a rate of 20 feet per decade.
2) Their spring activity has been happening earlier by about 2.3 days per decade. This is important because the plants, animals, and insects live in an intricate, perfectly timed dance. The caterpillars and other insects hatch just in time to eat the new leaves and the birds and rodents give birth just in time to eat the insects. With spring effectively moving, some are failing to adjust. Mis-timing has already caused dramatic reduction in some species.
3) Since 1976, the Antarctic krill populations, the basis of the food chain for southern whales, penguins, seals, etc., have been declining at a rate of 40% per decade.
4) Some areas have seen much higher temperature changes than the average. Southern Alaska has had a 4E – 5EF change. One result is that, due to a lack of hard winters, the spruce bark beetle has run wild, killing 40 million trees over the last fifteen years.
5) The Arctic ice is shrinking…a lot. It has suffered a 15% loss over the last 20 years. It is estimated that, over the last 30 years, the annual rate of loss has been 1 million km2. Over the same time period, the thickness of the polar cap has been reduced by 40%.
6) The Hudson’s Bay ice is retreating earlier, leaving less time for the polar bears to hunt ice seals and store up blubber for hibernation, when the cubs are born . A study of their pre-hibernation weights show a decline of 15 % with a corresponding impact on the cubs. At this rate, it is estimated that polar bears in the wild will be extinct by the end of the century, if not sooner.
7) Coral reefs are nominally colonies of polyps, but actually they are an ecological merger between the host coral polyps and an algae that feeds them. The polyps build their transparent skeletons and are fed by the algae which also gives them their wonderful colors. For a reef to be sustainable, the polyps have to be building their exoskeletons faster than the natural erosion is destroying them.
But the polyp can be a rude and touchy host. If there is a temporary rise in seawater temperature, the temperature-sensitive algae can’t feed the polyp and the polyp expels it, leaving the reef looking white. When the temperature returns to normal, the algae is allowed back in and everything (including the color) returns to normal. But, if the temperature stays high for as little as a couple of months, the polyps starve to death and the coral stays “bleached” a dead white.
Today, coral reefs all over the world are bleaching. Anything like an El Niño condition now can push vast areas over the edge. To take the biggest example, half of the Great Barrier Reef is severely bleached, with just 10% of live coral remaining. Other large areas show major losses. The forecast is that a further 1EC will see 82% of the reef bleached, 2EC will see 97%, and 3EC will see “total devastation.” And unless some more temperature-tolerant algae develops, the damage may be permanent, with the reef gradually eroding away.
Aside from the fact that coral reefs provide homes for the richest biodiversity in the oceans, it is worthwhile to remember that millions of people live on islands now protected by coral atolls.
8) Between the 1980s and 1990s, almost two-thirds of the 110 known species of harlequin frogs became extinct. The direct culprit was a fungus (batrachochytrium dendrobatidis), but it was warming that provided the conditions for the fungus to thrive. It is estimated the 1/3 of the world’s amphibian species are currently facing extinction.
9) The Sahel region of Africa (a band running across Africa that includes Nigeria, Chad, Sudan, and Ethiopia) used to be watered by monsoon-type storms from the Indian Ocean. Unfortunately, the Indian Ocean began to show global warming before anywhere else. As a result, the monsoons began to fail in the ‘60s. They have never recovered. The human catastrophes that we see in Sudan, Darfur, and Chad are far more a result of this catastrophic drought than any other single factor. And it is a chilling preview of what might happen if agriculture begins to fail in other, more populous areas.
10) Perth, in Southern Australia, is a city of 1.5 million people. For its water, it depended on winter rains filling up its dams. In the early part of the twentieth century, Perth’s rainfall averaged 338 gigaliters. From 1975 (one of the global climate’s magic turning points) to 1996 (another), it averaged 177 gigaliters or a decline of 48%. From 1997 to 2004, it has averaged 120 gigaliters or a 64% drop. To bridge the gap, the city has been pumping down its aquifer, which is nearing exhaustion.
11) The Gulf of Mexico has been warming, as have the other seas that generate and feed tropical storms. An estimate from MIT says that the amount of energy released by hurricanes worldwide has increased by 60% over the last two decades.
12) At the end of 2004 (i.e. spring in the southern hemisphere) and on into the coming months, it was reported that great stretches of the northernmost land in Antarctica was covered with grass, which had never been seen before.
Obviously, this list could be extended almost indefinitely. The scientific literature is full of paper after paper, all demonstrating that global warming is here, it is already affecting major systems on our planet, and that in the future it looks to get worse – fast.
Part of what makes all these papers really scary is that a lot of the consequences of global warming represent positive feedback situations that are hard to stop and harder still to reverse.
Consider, for example, the wonderful word albedo. Albedo is the ratio of the energy reflected back by a surface compared to the energy absorbed. Fresh snow reflects 80 – 90% of the incoming light, while water reflects 5 – 10%. Obviously the numbers are somewhat different for an ice cap and the open ocean, but polar ice still reflects most of the light that hits it while the ocean still absorbs most of it. In the case of the Arctic, as the ocean warms and the ice cap shrinks, there is less ice area to reflect the light and more sea to absorb it. So the ocean heats a bit more. Which causes more ice to melt. Which increases the area of absorption. And so on. Pretty soon the polar ice cap will be gone and the water will be too warm for it to reform.
The presence of this and many other positive feedback loops implies that many of the present trends we observe will only get worse and may, in fact, already be irreversible within any human time scale.
According to the climatologists, if we really put on an extreme effort to increase the efficiency of our use of fossil fuels, invest more in energy sources that don’t produce CO2 (such as solar cells and wind farms), and reduce our basic energy consumption, we will be able to achieve a stasis of CO2 in the atmosphere by 2050 – at twice the level we have now.
What does that mean? In 2004, a group from the University of Leeds published a study of the probable 2050 fate of 1,103 species, trees, crustaceans, mammals, etc., under various CO2 scenarios. At the lowest possible figure of warming, 1.4 – 3EF, roughly 18% of the species studied will be “committed to extinction.” At the midrange, 3.2 – 3.6EF, around 25% are projected to be doomed. At the worst case, over 3.6EF, more than a third are “committed.”
Then, of course, there is the final worry: According to the research into past climatic events, there are some invisible turning points along the road that cause cascade failures and lead to abrupt and major shifts, such as ice ages. In the past, these have materially contributed to, if not directly caused, massive die-offs of most of the species upon earth.
Bottom line is, no matter what we do, we will be passing on to our descendants a world that will be less rich, less healthful, and less hopeful. If we fail to do enough, we may leave them a harsh world of scarcities and brutal competition. And if we do nothing, we may leave them nothing as well.
God! What a legacy!