To anyone reading who wants to know what they can personally do--in rough order of decreasing impact:

https://citizensclimatelobby.org/ is doing really good work. They focus on a very non-adversarial approach, and are changing the minds of a lot of congresspeople about vital climate legislation. It's a very effective approach. Joining up with your local chapter and volunteering is a great way to spend your time and energy, if you have it.

A small thing anyone can do is sign up for https://projectgrandcanyon.com/ and call their congressperson once a month.

If you are willing to make a personal change, learn about veganism. You don't have to go completely vegan. It's great if you can, but if it's too scary, start with Meatless Monday and go from there. Rather than thinking about how to reduce meat, think about how to fill your diet with more meat-free options. Learn to make some tasty, filling vegetarian or vegan pastas, curries, and other recipes. Eat more starchy foods, whole grains, and beans.

If you can, and it suits you, move to a dense, walkable area of the city. This isn't possible or desirable for everyone, obviously.

The whole vegan thing was put into perspective for me when I learned that one intercontinental flight (roundtrip) a year has roughly the same CO2 footprint as going from vegan to "normal" meat consumption.

I'm still trying to be conscious about meat consumption (and will gladly adopt lab-grown meat) but that impact pales in comparison to avoiding plane trips.

The "something" to be done is very simple:

1) End fossil fuel subsidies

2) Apply or increase taxes on emissions

3) Invest the money from 1 and 2 heavily in nuclear, renewables and CO2 capture and storage for industries that can't just switch to clean electricity, negative emissions and "mild geoengineering" solutions.

Unfortunately, this is bad news for lots of existing multinational companies, and for lots of rich people, who lobby politicians hard to avoid this.

Also for jobs. A big issue in my country is the vocal subpopulation employed in coal mining, and the larger population believing that our coal industry is somehow nationally strategic; both of which will vote against anyone with any sensible climate strategy. I took a look the programs of our parties during last EU MEP elections, and sound treatment of climate issue is essentially inversely correlated with popularity of the party.

I like how the answers to your very legitimate question are either:

1) make a decision as a leader of a country / major player in the global economy

2) do small stuff that are very hard to quantify in effectiveness (eg call legislative representative, or go vegan)

3) dramatically change lifestyle

I fail to see how any of those are realistic. Especially 3 has never been shown to be implemented willingly by people, given that if not coordinated, will result in social isolation.

Make big changes now, or be forced to make them later. Stop supporting the meat industry. Take public transit or bicycle if possible. Avoid flying, driving by yourself. Avoid excessive consumption of disposable products.

There is no sustainable future where we get to keep our current lifestyles.

In addition to doing all those things on a personal level, each of them has a societal-level adjustment to pair with it:

* Stop supporting meat -- transfer those subsidies to carbon-friendlier foods and farming

* Make public transit free and much more widespread, fund it with taxes on pollution externalities from private transport

Transfer subsidies on fossil fuel power (and tax them) to wind and solar projects, too.

Doing this at a societal level would create a new set of winners and losers in the profit-making sense, of course; those would-be losers are the ones fighting these sorts of changes.