The Ministry for the Future: A Novel by Kim Stanley Robinson
This is a modern version of the classic utopian novel. The author zeroes in on one area they want to change. They propose drastic changes to enter their utopia. They assume everything else will proceed as planned and other areas will only improve for the good. It is comical how many parts were just missed or projected wrongly in old books.
This book starts with a massive heat wave in Indian. It is more than people can handle. People are dying. Indian is decides to act on its own and use geo-engineering to cool the earth. The rest of the world has agreed to reduce carbon, but they are slow to do it. The Ministry for the Future is an organization that is supposed to help drive the earth towards the future. However, eco-terrorist groups seem to have a bigger impact. They assassinate business and political leaders they don't like. They use weapons to take out military bases and polluters. They magically manage to stop before they get too carried away. (They must have some amazing will-power that other revolutionaries have not.) The world then creates a new carbon currency to help reduce emissions. This also encourages massive geoengineering efforts that in the end lead to actual reductions in emissions. The human population becomes increasingly equitable and hardly anyone has kids, with the human population declining significantly.
This Utopia is easy to pick apart right now. The terrorists group would either get out of control or get squashed. It is almost impossible for a terrorist-led revolution to stop at just the right place. The same goes with geo-engineering. Things could quickly get out of hand and lead to an accelerating ice age. Focussing on carbon alone may also miss many other areas of global impact that are much harder to manage. Even human population declines due to external events (like wars and disasters) often result in post-event baby booms equalizing the population. Good thing that this is a book rather than government policy.