The general consensus is that global warming is occurring and human activities are a significant causal factor in this matter. However, as with all hypotheses, it is always wise to consider the matter critically and rationally. To forestall any overly emotional reactions, I want to make it clear that I am not denying the consensus put forth by scientists. I am not a climate scientist and hence am not qualified to properly assess the technical aspects of the matter. However, my area of authority is philosophy and that includes expertise in critical thinking and causal reasoning. Hence, I am qualified to assess those aspects of the matter.
We have been told by Al Gore and others that global warming is occurring, that we are to blame (in part) and that this is a bad thing. Each of these claims bears proper scrutiny.
First, is global warming occurring? The statistical data seems to bear that out and I will not venture to claim any expertise in this matter. When dealing with statistics, it is important to have a sample that is large enough for the purpose at hand. In the case of climate, the sample needs to be rather large. Weather is a matter of what is happening outside your window right now. Climate is a matter of what happens in the long term. It is well established that the earth’s temperature varies and has varied in recent years (most famously during the Little Ice Age ) as well as quite radically in the distant past (in the ice age). To show that global warming is occurring what would be needed is evidence of a clear and enduring trend. Without such a trend, it could not be said that the earth is warming, cooling or staying the same. As noted above, the evidence seems to be that the average temperature has been increasing. However, as some are quick to point out, this year has included record colds and shows signs of being a cooler than average year. Some take this as evidence that global warming is not correct or even that it is a hoax. Some people have noted Al Gore’s strange silence now and have begun asking “where’s Al?”
It is reasonable to be critical in this. But, given that climate is a matter of the long term, it is important to be careful with such claims. Perhaps the cooling trend will give way to a warming trend. Perhaps not. Significant time is required to establish a trend in a meaningful way. Many scientists claim that this has been achieved and that we can be confident that the earth is warming. As such, this is the rational thing to accept. But, it is equally rational to retain a degree of skepticism-especially in a matter that is so fraught with emotions and politics.
The second concern is whether human activity is to blame or not. Even if warming is occurring, it is not the case that humans are the sole cause. After all, there are many other factors that contribute to the earth’s temperature and the extent of our influence on the world is not total. The important question is to what degree we are affecting the average temperature.
Causal reasoning is, as Hume argued, a rather tricky thing. It is difficult to determine the cause of an effect. Part of the problem is that working backwards from effect to cause is an inherently weak method of causal reasoning. This is why researchers prefer cause to effect controlled experiments. To oversimplify things, one main problem with going from effect to cause is that it is difficult to eliminate (control) other factors and thus find the actual cause or causes. In the case of a controlled experiment, these other factors are controlled so that any difference between the control group and the experimental group is most likely to be due to the alleged causal agent.
To use a specific example, consider the difference between a controlled experiment about running and a effect to cause study on health. If a researcher wanted to know about the effects of running, she would select a representative sample from the population and split this sample into two groups. The experimental group would be exposed to the causal agent in question-in other words, they would run. The control group would be matched as closely as possible to the experimental group (diet, genetics, weight and so on) but they would not be exposed to the causal agent in question-they would not run. After a suitable length of time, the two groups would be examined. The differences between the groups that are statistically significant would then be attributed to the difference between them-running. So, for example, if the blood pressure of the runners was lower than the non-runners at a statistically significant level, then it could be said that running lowers blood pressure.
Now, this can be contrasted with an effect to cause study. In this case, healthy people would be found and matched with comparable non-healthy people. The two groups would be studied to see what the relevant differences are between them. At the end of the study, the differences would be said to be the causal factor(s). Of course, it will be difficult to sort out what is a causal factor from what is a coincidence. It will also be rather unlikely that one factor will be found as the cause or even a primary cause. This is because, as we know from experiments, many factors are involved in health.
In the case of attributing climate change to humans, the overall model is an effect to cause study. We have global warming and it is inferred that human activity is a causal factor. However, we know that climate change occurred prior to the existence of humans as well as before we had achieved a significant level of technology. As such, there is room for doubt in regards to the claim that humans are a significant contributory factor in regards to climate change.
It can be countered that there is evidence that the by-products of human civilization (mainly CO2) are believed to cause climate change. This is known because non-human sources of CO2 are believed to have caused climate change in the past. Naturally enough, there is room for doubt here as well. This is because there are other factors that impact the climate, such as solar activity. As such, it is still reasonable to consider that other factors might be more significant than human activity. It is important to be fairly confident in our role before we start planning what we should do. If our role is significant, then we should take the appropriate action. Of course, the appropriate action is a matter of value and not science. Science, as scientists often point out when subject to moral criticism for things like nuclear weapons, is not concerned with ethics as a field of study. Hence, deciding what we should be aiming at doing is a matter of ethics and practical concern. This leads to the final concern.
The last area of concern is whether global warming is bad for humans. While this requires determining what is good and bad, it seems safe to begin with the assumption that what is harmful to humans can be considered bad. We have been told that global warming will flood cities, contribute to an increase in disease, lead to famine and all manner of other problems.
Obviously, if this is true, then we should do what we can to fight the temperature increase. This would be both prudent and right.
However, there is a concern worth noting. The Little Ice Age was rather damaging to humans. Crops failed, livestock died and people became sick. Cold is, as history shows, perhaps even more damaging than warmth. Perhaps it is the case that human activity is helping to prevent the cooling of the earth. If this is true, then it would be in our interest to keep things warm enough so that conditions remain to our advantage.
This does raise an interesting point to consider. If we, as a species, have the power to affect the environment on a global scale, then this is a power that we need to understand and learn how to control. While many would say we need to cut down on our impact on the climate, there might well be times when we should step up our impact. Again, consider the Little Ice Age as well as the time when much of the earth was covered in ice. Also consider the times when volcanoes radically affected the climate. These climate changes pose a threat to humans as well as other species. Unlike other species, we have the capacity to reason on a large scale and apparently the power to shape the climate. This means that we need not be passive victims of climate change-we can take an active role in protecting ourselves and other species. At this time, this role might be to act so as to offset global warming. If conditions change, our role might be to offset global cooling.
Obviously, we need to research this matter very carefully and take due care in our actions. As history has shown, it is all too easy to do terrible damage out of ignorance (witness the terrible pollution of the past and the present).
Some people might argue that we should not alter the environment. While I agree that we should not damage the environment, there is significant difference between damaging the environment and changing it in ways that are beneficial to us. As a species, we strive to survive and flourish. It would be unrealistic and actually immoral to expect humans to simply endure whatever the environment throws at us without taking action. Anyone reading this agrees with me-in behavior if not in belief. After all, you need to be using a computer to read this-think about what that entails.