May 17 2019

The Climate is Always Changing

Whenever the issue of climate comes up on this blog (or even just in the comments on unrelated articles), climate change deniers make an appearance. Consistently they use terrible arguments – relying on straw men, factually incorrect statements, deliberately confusing and blurring the lines, and committing just about every logical fallacy. They are also the same recycled arguments I see over and over, regardless of how many times they are refuted. That is how you know a position is intellectually dishonest, it never changes. It just moves around to the same repertoire of refuted positions.

A systematic refutation of these bad arguments requires a book, and there are many good resources out there, but I just want to focus on one argument in this article – the notion that the climate is always changing. This, of course, is true. It’s simply not a refutation in any way of the scientific position of anthropogenic global warming.

This is one of the many positions of the deniers. First they will argue that the climate is not changing. When the evidence for that is too irrefutable, then they say that it is always changing. This is also where the unmitigated hubris comes in – they bring up the point that there are natural trends in climate change as if this is news to anyone. Oh really, you don’t say? The climate naturally changes? I wonder if the world’s climate scientists, who have dedicated their careers to thinking deeply and carefully about things like the climate, have ever encountered that notion before. You should tell them.

Or, this is just a suggestion, you can take a moment to try to understand what scientists actually think rather than just swallowing science-denying propaganda whole. If a scientific idea is comprehensible to you as a non-expert, it’s a pretty good bet the experts have thought of it. You certainly shouldn’t assume that they haven’t, or you are somehow smarter than all the climate scientists in the world. Seriously – get some perspective.

In fact, the question of whether or not current climate trends can be explained by natural phenomena or forcing is the very scientific question at hand. That is what climate scientists spend their time researching and debating. The conclusion of current warming is anthropogenic was arrived at only after every known natural source of forcing was ruled out by specific research.

It is not, for example, solar forcing. Solar radiation has been decreasing over the last 50 years while temperatures have been increasing.

It is also not simply a natural trend, warming since the end of the last ice age. As you can see by the graph, current warming is way out of proportion to anything historical. It is too rapid, with higher CO2 levels than in the last million years. And it’s not a mystery why this is happening – we are putting billions of tons of previously sequestered carbon back into the atmosphere, shifting the balance in favor of greater heat retention. It would be surprising if warming weren’t happening.

This is usually where deniers shift to their next position – after saying the climate is not changing, then it’s always changing, they say, well, what if it is changing and we’re causing it. How do we know it will be a bad thing? There is no perfect climate for the Earth. It has been warmer in the past. The Earth will be fine.

This is nonsense, because it is a straw man that completely misses the point. The Earth itself will obviously be fine with higher carbon levels in the atmosphere. Sure, there will be a massive extinction event (which we are already in the middle of) but in a million years a new equilibrium will be reached.

The point is not that the climate is objectively optimal and should never change (which is impossible) but that humans have built our civilization around the current climate. Rapidly changing the climate is bad for humans, because it will cause a lot of problems for our civilization.

One problem is shifting optimal zones for agriculture. As temperatures rise, our crop production will no longer be best adapted to the climate, and the best zone for growing certain crops will shift away from the equator. We have enough problems growing food for over 7 billion people and increasing, and shifting the climate is an added burden we don’t know. Some raise the point that increased CO2 actually increases plant growth, and this is true, but the net effect is still likely to be negative.

Increasing CO2 can reduce the nutritional quality of crops, increasing temperature can reduce yield, and cause increased drought and extreme weather which are bad for crops. Further, some weeds will do better in the warmer and higher carbon atmospheres, presenting another challenge for farmers.

We also built many of our cities along the coastline. Rising oceans are likely to displace millions of people. There is no one “correct” coastline or sea level for the Earth, but if we don’t want our coastal cities to be flooded it’s best if sea level does not change rapidly.

Also, some cities and locations will simply become too hot for human habitation. The number of people living in areas that will experience temperatures that are potentially fatally hot will increase, causing further displacement.

The fact is, we are trying to support over 7 billion people and growing on this planet. This requires an optimal use of some resources, especially agriculture and water. We have a massive infrastructure to support our civilization, and rapidly changing the climate is going to be incredibly costly. We don’t know exactly what will happen when, but scientists are getting an increasing good estimate.

All of this means that global warming is likely to be very expensive to deal with. That’s why it’s always frustrating when deniers say things like, there’s no reason to harm our economy trying to mitigate climate change. This is wrong on many levels. First, there is no need to harm our economy to reduce the pace and impact of climate change. Most proposals involve simply accelerating the pace of technological advances toward a greener energy infrastructure and costs savings through greater efficiency.

Such things should not be considered a cost, but an investment. The difference is that an investment pays dividends in the future. Economists have been increasingly weighing in on the question, and the prevailing opinion is that climate change is going to be massively expensive. Our GDP will take a hit, and there will be huge incurred costs, including health care costs. Further, our economy will benefit from investments in green energy.

Deniers want to frame the debate as the climate vs the economy, but both of these considerations are actually on the same side. Developing and deploying cleaner energy is good for health, for quality of life, and for the economy. It is only vested interests in dirty old technology that is holding us back.

So yes, the climate is always slowly changing. But that does not mean it’s OK to rapidly change the climate in a way that will be disruptive to the massive infrastructure we have built for our civilization. Mitigating this anthropogenic climate change is also a win-win. But still we lack the political will, because of sloppy and motivated reasoning.



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