When we hear about global warming these days, it’s usually about melting ice in polar regions or rising ocean levels, which has already had some disastrous effects. The global warming denialists continue to call it a “scientific controversy”, which it isn’t, and resist all efforts to halt or reverse human activities that may contribute to climate change.
Some scientists have speculated whether it’s too late to reverse global warming, since the earth has a strong positive feedback mechanism where as it gets warmer, things happen to make it even warmer. For example, ice reflects sunlight, reducing the amount of heat absorbed by the earth. As the ice melts, and is replaced by dark land or water, more heat is absorb, melting more ice, then absorbing more heat. Once the earth hits some tipping point, it may be impossible to reverse course.
Another area of concern is that if the planet warmed just enough to cause a massive release of methyl clathrates, a solid form of methane locked in the deeper parts of the ocean and a more potent form of greenhouse gas than CO2, global warming would become a runaway event. This is another positive feedback mechanism, where the warmer the earth becomes, more methyl clathrates will be released from the ocean, making our planet warmer still. In fact, the Permian-Triassic extinction event, 252 million years ago, may have been caused by a sudden warming of the earth that released massive amounts of methane, which made the earth almost impossibly hot to sustain life.
Lucky for humans, we have evolved both physiologically and culturally to deal with a huge variety of of climates. We evolved brains that allowed us to make clothing for cold and air conditioners for the heat. We build all kinds of structures to deal with a wide range of environmental conditions. Humans survived the last glacial maximum, huge volcanic events, and various other ecological pressures.
Global warming may become so rapid that we may not be able to adapt (not in the evolutionary sense, but more culturally) to the speed of what’s happening to the earth. Can we adapt, as a species, to reduced food supplies? Areas of the earth that feed the planet may become deserts, or underwater. Fish and other ocean food stocks may crash even further than they do now, since many species have evolved to survive the current environment pressures. Evolution is very robust, but it takes time, so maybe a stock of coldwater fish have a gene pool that allows a tiny portion of their species to survive warmer oceans, but for that to produce a viable food source may take thousands, if not millions of years. Global warming has already start to deteriorate coral reefs,one of the key environments to maintaining healthy sea life populations. It’s becoming clearer that the warming of the planet may stress human life in a way that could only be imagined by a significant environmental event like a meteor impact or megavolcano.
One area of global warming that has not received the press that it deserves is the effect on healthcare worldwide. It’s not just poorer countries in tropical areas, but also northern, developed countries. In 2003, over 70,000 people died from a heat wave, when Europe was hotter than it had been in nearly 450 years. Even setting aside the massive lost of grain crops in Europe that year, the health care system was just barely able to keep up with the number of patients.
In poorer, less developed countries, the situation may become apocalyptic. Not only will malnutrition spread as food becomes harder to obtain, but diseases such as dengue and malaria will infect more people. Malaria is beginning to invade highlands of some African countries, where the disease was unknown, because the mosquito host can survive in areas that used to be cooler. Those countries already inadequate health care services will be strained beyond the ability to adapt. Many poorer parts of the planet rely on the goodwill of wealthier countries in providing healthcare workers, equipment and medicine. But if the healthcare systems across the globe get strained, it may be impossible to help everyone.
The USA seems to be intransigent about dealing with climate change (thanks to the nonexistent scientific controversy), but substantial and serious healthcare issues loom with a warming climate. For example, malaria has been eradicated from the USA since about 1950. But there is an increased risk of malaria as more tropical malaria-carrying mosquitoes enter the southern US. Europe is reporting more malaria cases contracted in the continent. Though malaria is ultimately curable, it is a difficult disease, and would put stress on a medical system that is unfamiliar with the disease.
As heat increases, water supplies decrease, food becomes more difficult to obtain, and more tropical diseases invade more areas, the healthcare systems of less-developed countries will be completely overwhelmed, pushing most of these areas over the edge of survival. But since the same effects will happen in more developed parts of the world, with more diseases (like malaria) for which the healthcare systems are unprepared, the death rate from the side effects of climate change will rise dramatically.
Even extreme heat itself will increase the death rate. For example, just 2 days of extreme heat in the US increases the death rate by 5.74% over the rate during “normal” weather. If there are weeks or months of extreme heat, the 70,000 deaths in Europe will seem to be a minor issue compared to what will be experience in the near future.
Can Homo sapiens adapt to this new environment? It depends. Canada, for example, might become the breadbasket of the world, because more land in the northern part of their country will become arable. But then again, if the planet’s feedback mechanisms go awry, then even Canada may also become a huge desert. But if diseases, from parasites to bacterial and viral infections, increase, especially in areas where humans are less resistant to them, food and freshwater supplies may be the least of problems for the healthcare system.
It’s difficult to not sound like this is some Hollywood disaster movie, but it’s clear that the global warming denialists aren’t thinking through all the possible consequences. The risk of a horrible outcome to the planet (in a relatively short period of time) should far outweigh the potential economic cost of ignoring global warming. Most scientists are not absolutists. For example, we might be wrong on anthropogenic (human-caused) climate change, but so far, there is no evidence that we are. Maybe the earth has a feedback mechanism that balances climate change that is unknown to us, but again, there is no evidence. But the denialist believe (like a religion) that climate change is impossible, or is not the fault of humans. Let the oil companies find more oil to burn, let the car companies build environmentally inappropriate SUV’s, and don’t worry about the coal-fired power plants. But if the denialist though that there’s only a 1% chance that the science is right, it should be enough to say, “maybe we should reduce carbon output, just in case, because if global warming is real, our children and grandchildren will suffer.”
Well, at least some human 500 years in the future will be writing some interesting paper on human evolution. Unfortunately, there might not be many people to read it.