Are humans already too late to stop climate change?

Main topic: Science

Other topics: Climate change

Short answer: We don't know for sure. The science says that there are multiple 'tipping points' that could cause the climate to suddenly change into a much worse - and possibly irreversible state - but as we continue to heat the planet, we don't know how close we are to one of those limits.

We don't really know for sure.

The problem with climate change is that it's not a simple matter of more-CO2 => more-temperature => more-harm-to-the-planet.

Some things are "positive feedback" or "tipping point" problems - where you can make a small change, and not much happens - but create just a slightly larger change and suddenly very bad things happen.

That means that if the science and our data measurements are 'off' by a tiny amount - it could mean that we're very close to a tipping point from which there may be no recovery.

To pick just one example out of many - the process which removes the most CO2 from the air is algae out in the oceans. Algae prefer cool water with a neutral pH (not too acidic, not too alkaline). This is why you see such "beautiful, sparkling blue water" in tropical paradises. The water there is too warm for algae - so the water isn't green and soupy - it's clear and sparkling.

So as we increase the CO2 in the air - and temperatures start to increase - algae which are surviving in water close to the tropics - but not too close - start to suffer from overly-warm water - and die off. More sparkling blue water is all very well - but now there is less algae to consume the excess CO2.

So what we have is a nasty situation - you push up the amount of CO2 a bit - the oceans warm a bit - some amount of algae die off - which means that less of our CO2 is absorbed by the oceans - and more goes into the atmosphere - and we get more heat, fewer algae, less CO2 being absorbed...round and round until there is sparkling blue water everywhere - and we've completely killed the planet in an irrecoverable way.

But trying to figure out EXACTLY how much CO2 produces EXACTLY how much heat which kills of EXACTLY how many algae...we can't know that information to any useful degree of precision.

Then we find that CO2 dissolves in water - to form Carbonic Acid (which is what puts that sharpness into the flavor of carbonated drinks). But algae doesn't like acidic water - so now, as we put more CO2 into the air, there are two entirely separate reasons why the algae are dying - and each has it's own "tipping point". With the algae stressed in TWO ways - we're even less sure about whether we're close to a tipping point - or perhaps even past it.

There are at least dozens of these tipping points - loss of bright white snow and ice means we're reflecting less sunlight away - which pushes up the temperature which melts MORE snow and ice. Warming of the deep oceans melts "clathrate" deposits - which release methane into the water and then into the air - and methane is an even worse greenhouse gas than CO2 - so up goes the temperature and MORE clathrates melt. Thinks like the decay of peat moss that's released from melting permafrost...same thing.

Therefore - we MAY have already pushed any of a dozen climate-change buttons that start off this chain reaction...or maybe the planet is resilient enough to allow us to push things a little bit further. We don't know...and we won't know until it's too late.

But what is certain is that the button can be pushed...and once pushed, we're in very big trouble.