Cumulative and (probably) irreversible

This post may be written more in frustration than anything else, but I’ve had some recent discussions that have made me wonder if even those who spend their time thinking/writing/commenting about climate change fully appreciate that it’s a cumulative problem that is probably irreversible. Or, maybe, if they do, that they don’t fully appreciate what this really means.

It is now pretty clear that the overall level of global warming is going to mostly depend on how much CO₂ is emitted in total; i.e., it depends on cumulative CO₂ emissions. This leads to two basic conclusions; stopping global warming requires getting CO₂ emissions to zero (i.e., net zero), and keeping global warming below some level would require doing so while also limiting total emissions (i.e., a remaining carbon budget).

It’s also been clear for quite some time that global warming is probably irreversible on human timescales. The changes that are induced will probably persist for many generations. If emissions don’t get to zero before the impacts become extremely severe, it will be too late to stop them from getting even worse. Yes, there are some possible technological fixes, but they carry their own risks and have never been implemented at a suitable scale.

So, if we decide to follow a pathway that will lead to higher total emissions than might otherwise be the case, we will be committing future generations to a level of warming that could have been avoided and to impacts that they might not have had to experience.

I realise that the above doesn’t immediately tells is that we should focus all our attention on emission reductions; there are many other important factors to consider. How do we do so in a way that is fair and that doesn’t do more harm than good? How do we do so in a way that also allows communities to improve their resilience and reduce their vulnerabity? Do we accept that there might be circumstances where it is still preferable to continue using fossil fuels? etc.

However, even though these other factors can be very important, it still seems crucial to be aware that, at the end of the day, the amount of global warming that people will experience will ultimately depend on how much CO₂ is emitted in total, and that the resulting changes, and impacts, will probably persist for a very long time. I know this is clichéd, but there really isn’t a planet B and, if we’re not careful, we could end up substantially, and irreversibly, changing the climate of this one.