I don't wish to sound defeatist, but I fear that we've already passed the point of no return for avoiding Very Serious consequences.
We have fed massive amounts of carbon into the atmosphere over the past decade, more than any decade in the past, and our rate of emission continues to increase. Admittedly the double delta (the rate of change of the rate of change) has now gone negative, but the fact remains that an enormous amount of damage has been done, and continues to be done.
We are already seeing preliminary consequences in the form of heating, excess precipitation, "strange" weather, and this is already incurring costs, both economic and upon the climate. Flood defences aren't cheap, nor is rebuilding homes and infrastructure.
On the climate cost front, for instance, the three springs in the UK and elsewhere killed or damaged an awful lot of trees this year, which decreases the amount of carbon reabsorbed - this kind of feedback cycle isn't really anticipated by current models which rather look at broad variables like "is the average temperature within the average range within which trees can live" - not "will we have trees sprout considerably then be frozen twice before succeeding in one year".
We have giant holes opening up in the tundra which are spewing forth enormous amounts of methane which again, wasn't really anticipated, and is another positive feedback loop.
In terms of what you can do - learn skills that are useful in a post-post-scarcity society. I don't think we can avoid drastic climate change at this point, but we can sure as hell try to survive through it as best we can - and it's likely to force dramatic lifestyle changes, to put it lightly.
If you want to do something directly which may abate but not avert the impending disaster, find a way to promote political and popular will to actually do something urgently and internationally - most are still lukewarm on the topic, and will only actually start responding when things get nasty indeed - and then likely only on a local basis and in an uncoordinated fashion.
Sorry, that does all sound defeatist, but I think we're going to find ourselves investing an awful lot of time and energy in dealing with the consequences of climate change in the near future, rather than dealing with the root cause. That may end up being a permanent state of affairs - I can imagine that it could actually be turned to net economic benefit for some by generating employment in new industries (dike building will be big business), although many without the benefit of a coordinated response and the fortune to live in part of the world which cares to respond will suffer, greatly.
Humans have survived ice ages - civilisations and societies have not, to our knowledge - humans will likely survive this - but this civilisation - who knows.