Barack Obama believes that 0.0004 mole fraction of an essential trace gas (which all life depends on) threatens the planet.
Even if you subscribe to his mindless CO2 superstition, Obama already wrecked any prospect of a meaningful agreement when he agreed to let Chinese CO2 emissions grow until the year 2030. China is on track to be 50% of global emissions by 2030, and the US is on track to be less than 5% of global emissions.
US emissions have been decreasing since George Bush was elected. Obama has had essentially zero impact on US emissions.
The US has almost no control over global CO2. Obama’s EPA regulations and his fake Paris agreement are meaningless nonsense. They will have no noticeable impact on global emissions, which are increasing exponentially.
As with everything else Obama does, the Paris Conference is just one more big lie.