The central crisis facing international attempts to mitigate dangerous climatic change due to mankind’s emission of greenhouse gases and other perturbations of the Earth’s energy balance is the political unpalatability of enacting steep cuts to carbon-intensive fuels like coal and oil. As long as these energy dense but planet-polluting fuels do not reflect the real world cost of their use, it remains difficult if not impossible for politicians to justify ignoring their “cheap”, always-on, baseload power in favor of “costlier” renewable and intermittent sources like wind and solar panels. This is especially the case as transitioning away from carbon intensive fuels is portrayed to be in direct conflict with rapid economic growth, in both the developed and developing worlds. (Nuclear remains likewise politically unpalatable due to environmental and security concerns, though many are trying to rectify this.)
CO2 is far from the only greenhouse gas/radiative forcing that humans are mucking about with, nor is it even the most “powerful” on a molecule-by-molecule basis. These other forcing agents, from black carbon to CFCs/HFCs (so-called Montreal gases) to methane, may represent “low-hanging fruit” in mitigating future climate change. That is to say, they can be reduced independently of large cuts to coal and oil usage, often with concomitant benefits to general public well-being, making their reductions a politically viable option even among developing economies like India and China that so far are refusing to commit to reducing CO2 even as they dramatically increase their share of its emission. Some, myself included, have seen these non-CO2 forcings as a potential bridge towards overall emissions reductions that developing and developed countries can address while renewable infrastructure matures and a rising price on carbon is put in place.
However not all forcing agents are equal. CO2 hasn’t been singled out to specifically penalize archetypal environmental boogeymen like coal and oil companies, its importance in discussing the mitigation of climate change is based upon its role as the climate’s “biggest control knob”. What CO2 lacks in warming ability per molecule, it makes up for by being positively Methuselan in terms of atmospheric residency. David Archer has popularized this problem in his descriptions of CO2’s “long tail” (my emphases):
The climatic impacts of releasing fossil fuel CO2 to the atmosphere will last longer than Stonehenge. Longer than time capsules, longer than nuclear waste, far longer than the age of human civilization so far. Each ton of coal that we burn leaves CO2 gas in the atmosphere. The CO2 coming from a quarter of that ton will still be affecting the climate one thousand years from now, at the start of the next millennium. And that is only the beginning.
The excess CO2 in the atmosphere at the next millennium may not be the exact same molecules that came from our power plants. Some of the CO2 from fossil fuels will have been taken up into trees, or deposited in soils. Some will have dissolved in the oceans. But, as this book will explain, the CO2 concentration in the atmosphere at the next millennium will be higher if that coal is burned than if it is not. About 10% of the CO2 from coal will still be affecting the climate in one hundred thousand years.
By contrast black carbon stays in the atmosphere for days to weeks, and CFCs generally have a residency of decades (22-111 years), etc. And of course, we’re producing and projected to produce enormous amounts of CO2 compared to preindustrial levels and relative to other forcing agents. So we’re left with political unpalatability of sharp cuts in coal and oil-based CO2 emissions compared to the relative “ease” of reducing black carbon, Montreal gases, etc. vs. the very real difference in long term climatic change CO2 is capable of relative to these other forcing agents. It may be possible politically to reduce a significant amount of shorter term climate disrupting emissions, but this leaves the heavy- arguably the most climatically important- lifting yet undone.
Next, we’ll look at some questions relating to these potentially conflicting, potentially complimentary tensions, like: How much of a difference can the non-CO2 emissions reductions make? Is it even possible to phase out coal use in a country as dependent on coal as the US? If the US decided to act unilaterally would it make a difference in coal use?