Cancer has been on my mind rather more than I’d like, so this week it occurred to me to check out the links between climate change and cancer. I figured there probably would be some. Horsemen of the Apocalypse tend to roam in packs.
It didn’t take me long online to find out that yes, there are links. There’s even a whole chapter on the subject in a report published by the National Institute of Environmental Health Sciences. Except where otherwise noted, this information in this article comes from that chapter.
Climate Change and Cancers
“Cancer” is not a single disease but rather a whole category of diseases. All cancers have some things in common, but causes and effective treatments both vary. It’s even possible to have two different cancers at the same time, in which case the two need to be treated separately, because what works for one won’t necessarily work for the other. So it’s not good enough to ask whether climate change causes or exacerbates “cancer.” We have to look at which (if any) cancers are involved.
We also have to be clear about what we mean by “involved.” I have not found anyone claiming that being too hot, too dry, too wet, or too wind-blown can actually cause any cancer (though these cause plenty of other health problems!), but there are indeed cancers that would be more rare if we weren’t heating the planet.
Some skin cancers are caused by exposure to UV light, and the thinning of the ozone layer caused more exposure. The main ozone-depleting gasses are also greenhouse gasses. Had those gasses not been released, there would be less climate change and less skin cancer. Higher temperatures also tempt people to expose more skin to damaging UV rays.
The other big climate-related cancer is lung cancer, which can be caused by air pollution. Many common air pollutants are also greenhouse gasses. Wood smoke, as in what comes off of all these wildfires we have these days, may also cause lung cancer.
So, it’s official; more climate change means more lung cancer and skin cancer.
A less direct source of risk is that climate change can make it easier for people to contact certain pollutants. For example, floods caused by the more extreme weather we’re getting often sweep up some very serious pollutants. Exposure to floodwater, or drinking water or soil contaminated by floodwater, could therefore involve exposure to various carcinogens. Higher temperatures make some pollutants more volatile, driving them out of soil or water and into the air. When the pollutants in question are carcinogens, that translates into more cancer, or more cancer risk in places that used to be relatively healthy.
You knew there would be complicating factors, didn’t you? One source of complication is that there’s a lot we don’t know about what causes various cancers or how the causal connection works. There are a lot of pollutants that might be carcinogenic, but we don’t know, or we know they cause cancer, but not how dosage relates to risk. Will one swim in contaminated flood water do it? We don’t know.
Another major source of complication is that a lot of the processes being advanced to lessen anthropogenic climate change could also carry increased risk of cancer. Nuclear power is one obvious example. Less obvious is that cadmium is used in the manufacture of solar cells, and cadmium is a known carcinogen. Hydrogen fuel cells could pose a problem if the cells leak, since hydrogen is an ozone-thinning gas and thus an indirect skin cancer risk. Even biodiesel could be a threat, since the chemical profile of its exhaust is different than from petrodiesel, and we really don’t know what breathing in that exhaust might do.
It’s not that we’re damned if we do, damned if we don’t–it’s that the picture is complex and we don’t understand it very well, yet.
What we do know is that using less energy from any source is the best bet for reducing anthropogenic climate change without causing secondary problems. But we knew that already. And using less energy isn’t a popular option.
Specific Pros vs. Vague Cons
While cancer is probably not the worst thing that anthropogenic climate change is doing, it’s definitely on the menu. If you have been touched by cancer in some way, you know how awful the malady is. It’s like a war zone breaks out inside your family and no one else can see or hear the bombs going off, the infrastructure breaking. We know, now, that the further anthropogenic climate change goes without somebody doing something about it, the more cancer there will be.
The problem is that not only don’t we know who is going to get cancer, we also have no way of knowing which cancers are climate-change related. That’s what increased risk means. We might know how many more cancer diagnoses there are, but we won’t know which of those people would have gotten cancer anyway. It’s hard to get emotionally involved with a statistic. You can always convince yourself that it applies to somebody else.
Contrast that with the concrete, obvious benefits of using fossil fuel–if you drive to the store for a loaf of bread, you know perfectly well who got that loaf of bread. If you own a petrochemical company, you know perfectly well who made a very comfortable living. You don’t know who got cancer from that same tank of burnt gas.
The same problem occurs with any cost/benefit analysis of fossil fuel use. If we’re going to get ahead of this thing, we’re going to have to make those unpredictable cancer cases seem just as real as that loaf of bread, that comfortable living.