Except China emits more than double the CO2 that America does. The USA emits less today than it did 10 years ago, while China's emissions grow exponentially. The original point was that there is a lot of work to do outside of rich, western countries.
I'm not saying America is blameless, or that it is all China's fault. I'm saying putting all of your effort and focus on America while ignoring the growth of the world's largest polluter will not solve the problem.
The USA can afford to emit less than it did 10 years ago precisely because it has emitted so much in the past and its economy is basically built. Any bemoaning about China or other currently-developing countries that doesn't also talk about how we should also be helping them bootstrap themselves with more advanced systems is just privilege at having gotten there first and pulling the ladder up behind us.
Isn't renewable energy generally cheaper than coal at this point?[1]. You're right, that we have done the work to research, develop, and manufacture renewable energy sources. Now all the rest of the world just has to buy the thing that is cheaper.
Yes, renewable is cheap, but also unreliable. And storage to manage that unreliability is, per your link, more expensive than the corresponding fossil fuel plants. It's either that or drastically over-provision the renewables, which then has to be factored into the cost.
Right now, the cheapest approach from scratch could maybe consist of:
1. Over-provisioned renewables,
2. connected to a large-area grid to mitigate local-scale negative impacts to renewable productivity,
3. with enough fossil fuel capacity to basically serve as "storage" and bridge large-scale negative impacts to renewable productivity.
But, of course, China is not building from scratch -- they've been at this for decades. And the inversion of prices between renewables and fossil fuels is a fairly recent one.
You can add US for comparison. China's emissions have been plateauing for the past 10 years, while the US is going down. Per-capita, China is still less than half of the US, so it'll take a long time before the US catches up, if ever.
And if you choose to normalize by GDP, China emits twice as much as the USA[1][2]. China has lots of very poor people, bringing down the per-capita average, but the USA has a more carbon efficient economy.
The point I tried to make is that it doesn't matter if it's the us, china, france, russia, etc. Blaming brazil isn't the solution, they're only doing this because china (in this case) are prioritizing cheap soy over the health of the Amazon.
The exact same argument is true for palm oil in indonesia; blaming indonesia for destroying borneo and sumatra isn't going to fix the problem when it's all being exported to the EU and india.
It is incumbent upon those with the power to stop degrading the environment to do so. Where the Amazon rainforest is concerned, that's Brazil.
Getting every nation which might want cheap soybeans (all of them, to a first approximation) to agree to stop buying from Brazil is a complex coordination problem with rewards for defection. Getting Brazil to stop cutting down the rainforest for the profit of agribusiness is coordinating the policy of a single nation; still difficult, just not completely intractable.
Brazilian soybeans rely on genetic modification to survive in the sweltering climate. Monsanto is perhaps the best target here.
I'm not saying America is blameless, or that it is all China's fault. I'm saying putting all of your effort and focus on America while ignoring the growth of the world's largest polluter will not solve the problem.