There are many who scoff at the notion that climate change is really happening; they are one type of ideologue — the perpetual skeptic impervious to reason and scientific inquiry.

But there is another type.

This ideologue believes that massive (as much as 70%) and immediate reductions in CO2 represent the only possible option for dealing with climate change; otherwise, we are all doomed. Whereas most environmentalists focus considerable ire on the former type, this piece is dedicated to the latter.

Climate change is probably the most challenging environmental problem humanity has ever faced, due to the potential scale, the source of the problem (energy use), and the coordination needed to address it. The hole in the ozone layer was actually as serious an ecological risk (since UV rays are toxic to virtually all living creatures), but the number of pollutants that contributed to it were relatively small and confined to a few industries, and discontinuing their use wasn’t extremely costly.

On the other hand, every human activity uses energy, and with both growing populations and economic growth, decreasing CO2 emissions is much more difficult and potentially costly.

In addition, whereas we were able to directly observe the hole in the ozone layer and attribute it with certainty to the use of certain chemicals, climate change is harder to measure, given cyclical climatic trends. Most importantly, it’s harder to know how much human activity contributes to climate change and, hence, how much lower emissions will actually decrease the planet’s warming.

Anyone who approaches the issue of climate change rationally must acknowledge that it is theoretically possible there are scenarios where it is not best to head down the path of radical emissions reductions.

Why is this?

Because there are certain circumstances under which the cost of reducing emissions does not measure up well against the benefits. At its heart, climate change policy must have some element of a cost-benefit weighting. If the costs far outweigh the potential benefits, strategies besides emissions reductions may be preferable, like adaptation. This is not to say that this is the case, but that it might be.

Of course, there are also equity concerns, because climate change is happening primarily due to the actions of the developed world, but are likely to disproportionately harm the countries of the developing world. But here again, it is not automatically evident that an emissions-reductions strategy is the best course. Perhaps helping poorer countries to develop, fight disease, improve their technological infrastructure, allow greater immigration to rich nations, or any combination of policies would be a better use of the world’s time, energy, and resources than massive emissions reductions. Maybe not.

It may very well turn out, based on both science and economics, that a massive emissions-reductions regime is the best policy. But those who jump to this conclusion without examining all of the facts are ideologues just like those who deny the existence of climate change in the first place.