The major flows of sea water (e.g. Gulf Stream) are at risk of changing completely with the temperature changes, which means dramatic changes in climate for Europe (colder), USA (warmer) (for example) are possible. Who knows - and the answer is nobody really.
The acidification of the oceans as they absorb more and more CO2 is making it harder for phytoplankton to grow. Take away this basic building block of the ocean ecosystem and the ultimate outcome is dead sea, with no ability to generate oxygen, and toxic gases emitted. That will change our atmosphere to be deadly.
These and so many others are not just exponential trends, but have unknown knowns (e.g. methane released from Arctic) and unknown unknowns that will magnify the impact. As people involved in high growth companies and the internet we understand exponential growth - but the politicians and even scientists are reluctant to understand and embrace the consequences.
Meanwhile we are still increasing, not decreasing CO2e emissions. Emissions need to decrease sharply now, to zero, for us to have a chance, and even then it's hard.
There is no political will. We are too comfortable. And then it will be too late.
We should ask ourselves the question - what can we do that's more important than helping to reduce global emissions? And then do something. There are lots of ways to help, and none of us can do it all, but we all need to do something, and take leadership roles to make the changes.