Greta, thank you for your thoughts. You are not wrong in your view of the hypocrisy of political leaders. However, you and the movement for climate action that you represent may be wrong about how seriously world leaders look at global warming.
Our leaders (both government and cooperate) know that warming is serious, and they understand the science; but the root cause may be viewed by all the leaders of our most powerful nations as a problem of overpopulation and not exclusively as a problem of producing energy with carbon-based fuel.
And while governments understand the science of global warming, they cannot see a solution that requires eight billion or more people to give up on growth and live with less as the world tries to transition over decades to alternative energy sources, including nuclear.
What you see as foot dragging on climate action may just be a reluctance to admit publicly how dire the climate situation has become.
Perhaps, China along with America, Britain, and Australia (and many other governments) have concluded that reversing global warming cannot be done by cajoling average citizens to move off carbon-based fuels if the result will mean people live with less during a generational transition, when there is not enough time left for a generational transition.
Even today Europe is facing a crisis with natural gas supplies and looking to protect their populations from having to do with less, which will mean that promised actions on CO2 mitigation get delayed or simply forgotten for now. That's the way societies and politics work.
Knowing this, it seems reasonable to speculate that the military and intelligence sectors of China and America are preparing for military conflict this decade as all the negative impacts of global warming accelerate.
Governments know that global cooperation with all its plans and promises that signify nothing will fail to stop atmospheric CO2 from crossing the next tipping point of 425 parts per million sometime between 2025 and 2030. The world will then shoot beyond 2 degrees centigrade of warming (on average) with some parts of the world (such as the Middle East, polar regions, etc.) experiencing warming well above the planet average. War in the Middle East seems inevitable as the world heats up further.
The question is: if it's not possible to persuade billions of people to "live with less" to reduce CO2, what are some alternative actions?
Biden assured the United Nations today (September 21, 2021) that war must be a last resort to solve problems. Nevertheless, cold logic might look at reducing the world population in murderous ways while some elites and other well-connected people ride out a global war of population reduction in bunkers and hideaways. The ruthless mind might have concluded that if the outcome of all current climate mitigation is unavoidable societal collapse and likely human extinction, then it is only prudent to take kinetic action through war to reduce the global population in a desperate means to reach a reset point of a few hundred million humans out in the wild and perhaps a hundred thousand bunkered away in New Zealand and other places with all the archives of science and years of rations to get the world restarted at some point in the future. War is politics by other means.