A conservative opposition to anti Global Warming policy is that it will lead to a "One World Government". This is often derided as a conspiracy theory.
Here is a thought experiment:
If my country (Australia) were to enact a law preventing the burning of fossil fuels, there would be a series of effects:
- Global fossil fuel emissions go down temporarily
- Global fossil fuel prices go down due to reduced demand
- Global fossil fuel emissions go back up as other countries take advantage of cheaper fossil fuels and use more.
I imagine that global consumption of fossil fuel would increase until the price raises back to what it was before the reduction in demand.
The net long term effect would be that global emissions stay about the same.
But the side effect would be that my country's economy would be decimated. The more strictly we reduce fossil fuels the more we will be injured.
Therefore, how can a country do any more than hurt itself by unilaterally reducing greenhouse gas emissions?
It seems that the only option is with treaties such as the Kyoto Protocol, Paris Protocol and various EU initiatives.
But these treaties have the same issue, only member states will reduce their emissions, this will drive down the demand for fossil fuels, which in turn will make fossil fuels cheaper for non-member countries (e.g. Russia, China, Iran, etc.) these countries will then consume more fuels. This will give them a huge economic advantage attracting more industry and migration etc. Eventually, overall fossil fuel consumption will return to normal.
The net effect is that any co2 reducing treaty will hurt the members and benefit the non members.
Also even if a treaty is established, the price of fossil fuels will drop, which will make evasion by private citizens more and more profitable. Governments will therefore need to spend increasing amounts of money to enforce the treaty on their citizens. A government could easily shirk its obligations by simply spending a minimum on enforcement and allowing citizens to get around the restrictions on burning carbon. The less a government spends on enforcing the treaty, the better its economy will do. The citizens of the less compliant member states will therefore "take up the slack" caused by the lower price of fuels caused by the more treaty-compliant states.
The only way of avoiding this problem would be a global team of inspectors and enforcers, with the power to direct policing effort and spending in the countries bound by the "treaty". Having a global power directing your countries police force and budget will be undesirable by any member state, so at some point, a member state will try to leave. If a state is a democracy, then it's people may vote to leave the treaty.
But if one member state is allowed to leave, the whole thing breaks down, as that state would benefit enormously from the now cheap supply of fuel, experiencing massive re-industrialization, and economic growth until it (and other dissenters, inspired by its economic boom) make up for the reduction in greenhouse emissions and renders the whole treaty a pointless exercise in enriching the non-compliant states.
Therefore, force will be needed, if necessary military force to override the will of that member state and its people, and keep the state a "member".
If the only effective political solution to global warming requires some kind of involuntary "treaty" organization, and this organization requires the final say on at least policing budget and policy in the member organizations, and the power to militarily force compliance, overriding the democratic will of that member state, isn't that by definition a "World Government"?
Any political solution that doesn't involve force will simply benefit every state that chooses not to comply and thus be self defeating.
I think trade sanctions may be proposed as a potential alternative to direct force. But then the economic damage of the sanctions would have to exceed the benefit of being able to freely use fossil fuels. If only one country left the treaty, and all world governments imposed sanctions this could indeed impose a big cost on that country. But since there would be a huge incentive for other countries to join the dissenter (free use of fossil fuels) they would likely soon have multiple willing trading partners, reducing the impact of sanctions.
Note that current climate treaties may not have been impactful enough to actually reduce the price of fuels globally yet. And if the relationship between demand and price is not linear, there may be some reduction in demand possible before price is affected. However current treaties haven't been impactful enough to avoid global warming either.
Also, let's leave out non-political solutions to global warming such as improved renewable technology being voluntarily adopted.