The first effect is that aerosols (smoke) in the atmosphere has been hiding about half of the global warming that we otherwise would have experienced. The acceleration in coal burning in Asia in the past decade has increased aerosols and, therefore, can explain the lack of increased warming in the past decade. However, this is a Faustian bargain because CO2 lasts in the atmosphere for hundreds to thousands of years and smoke lasts in the atmosphere for about 5 days. Therefore, when we stop increasing the amount of smoke we put into the atmosphere (like China wants to do now because of the crazily dangerous pollution they are experiencing), warming will increase faster than in the past (the devil will collect his payment).
The other effect, that also sounds good at first, is that atmospheric CO2 is not increasing as fast as our fossil fuel emissions. Somehow, the Earth is capturing more CO2 in "sinks" as we are accelerating our CO2 emissions by burning ever more fossil fuels. Dr. Hansen believes this is happening because the increased coal burning is increasing nitrogen in the biosphere and along with increased CO2 in the atmosphere, that is increasing plant growth productivity, especially in boreal and temperate forests. Sounds good doesn't it? Unfortunately, this is another deal with the devil because the carbon has moved from underground (fossil fuels) to terrestrial sinks where it will, again, last for thousands of years. So, as climate change advances and droughts, bark beetles, and other impacts move carbon from terrestrial sinks back into the atmosphere, there will be more carbon released than would have otherwise been the case. The devil will again collect his due.
Dr. Hansen concludes:
"Increased short-term masking of greenhouse gas warming by fossil fuel particulate and nitrogen pollution is a "doubling down" of the Faustian bargain, an increase in the stakes. The more we allow the Faustian debt to build, the more unmanageable the eventual consequences will be. Yet globally there are plans to build more than 1000 coal-fired power plants and plans to develop some of the dirtiest oil sources on the planet. These plans should be vigorously resisted. We are already in a deep hole -- it is time to stop digging."