The news about climate change these days is anything but good – at least if you’re rooting on the side of the long-term survival of species, ecosystems, and human civilization. President Trump has announced that the U.S. Government will be rescinding its acceptance of the Paris Accords, which had committed the U.S. to making steep reductions in its Greenhouse Gas (“GHG”) emissions over the next ten years. The quick analysis by climate scientists is that the loss of that commitment would mean a 0.2-0.3 degree Celsius increase in the 50-year worldwide average temperature rise – from about 3.5 degrees to 3.7 or 3.8 degrees. When one considers that, in order to avoid drastic consequences, most climate scientists figure that a 1.5 degree increase is all that can be tolerated without major repercussions, It means we’re all that much deeper in hot water (so-to-speak).
Interestingly, Trump did not say the U.S. would ignore climate change. Instead, he said that the U.S. commitment was a bad deal for us, compared to what other countries had committed to, and he wanted to see something fairer. To some extent, that’s a supportable position.
The Paris Accords were the result of a desperate last-ditch effort by the international community to avoid having to admit abject failure in addressing human-caused world climate change. Previous efforts had either been ineffectual or run aground on disagreements between nations with differing national interests. This time, rather than face failure, the world community opted to accept a “lowest common denominator” – something pretty meaningless that at least everyone could agree upon. The result was a voluntary agreement, with no real teeth, that allowed each country to decide for itself what it was willing to commit to. In some cases, like the U.S., the E.U. countries, and China, those commitments were fairly impressive – not good enough to reach the 1.5 degree goal, but at least a significant reduction in GHG production compared to staying with the status quo. In other cases, notably India, the promised effort was little more than eyewash – a token effort that promised little if any reduction in GHG production.
It’s interesting, and perhaps significant, that one of the two countries not to sign the accords, Nicaragua, did so not because the Agreement was too strong, but because it was so weak as to be practically meaningless. (Nicaragua, by the way, is already way ahead of most countries in lowering its GHG production.) To the extent the U.S. was committing to major reductions in GHG production while some other countries’ commitments were so minimal as to be laughable, Trump might have had a point, if he had demanded, as a condition for the U.S. staying in, that there be a minimum threshold of GHG emissions reductions to which all signatory countries would have to commit. That would have been a principled statement, and might have actually gotten at least some other countries to follow suit.
Instead, however, he put the U.S. withdrawal in the context of the narrow self-interests of U.S. businesses that might be put at a disadvantage compared to companies based, for example, in India. That’s neither an enlightened or principled position. If other countries were to follow Trump’s example, the Agreement would very quickly collapse.
What are the repercussions’ of President Trump’s decision? Well, to begin with, pulling out of the Paris accords is not simply a matter of tearing up a document. Withdrawing from the Paris Accords, like Brexit, is a complicated multi-year process. There is plenty of time for second thoughts, in addition to the 2018 Congressional elections and the 2020 Presidential election, before the U.S.’s exit becomes final. Meanwhile, if Trump is serious about caring about climate change and the environment (which he still claims to be), he ought to be pushing the U.S. forward on efforts at addressing climate change that don’t put U.S. businesses at a serious disadvantage. (Yes, there are such things, like putting a serious effort into developing cost-effective carbon sequestration methods.)
All that having been said, the worldwide temperatures are continuing to creep up, year by year. Some time in the not-very-distant future, they’ll very likely pass the 1.5 degree increase that scientists are warning about. What happens then?
Well, the Paris Accord negotiators were well-aware that the agreement they had reached wouldn’t get the world to where it needed to be on climate change. However, the agreement included a requirements that the commitment made be revisited every five years. The negotiators expected that in five years, the effect of climate change would be more evident, indisputable, and severe; and disregarding them would be less politically acceptable. As a result, the reasoning was that five years down the road, the commitments would become more meaningful, and perhaps the worst effect could still be avoided.
However, climate scientists have warned that at some point, we will reach a “tipping point” in climate change. As average temperatures continue to rise, there are numerous effects that will, in themselves, increase the rate of GHG emissions. In cybernetics, this is called a positive feedback loop. With public address audio systems, the result is the squeal you hear when a microphone is placed too near a loudspeaker.
Right now, the earth has natural mechanisms for sequestering – i.e., keeping out of the atmosphere – GHG. For example, the ocean’s waters contain vast amounts of dissolved carbon dioxide (or technically, carbonic acid). Further, as the atmospheric CO2 concentration rises, more of it gets dissolved. However, as water warms, its ability to hold dissolved CO2 decreases. Thus, as the oceans warm, along with the rest of the planet, they’ll release a huge amount of dissolved CO2 into the air. Similarly, as the permafrost – permanently frozen ground in the vast arctic tundra of Russia and Canada – warms, there is a huge amount of methane, generated from decayed prehistoric vegetable matter, that will likewise get released. This happened before, at the end of the Permian geological era, and resulted in a sharp temperature increase. Accompanying that was a huge mass extinction that eradicated a majority of then-existing life on earth. (This is shown in the fossil records from that time.)
Another way in which climate change is likely to affect sequestration is that vegetation is continually removing CO2 from the atmosphere and converting it to organic matter through photosynthesis. While a lot of this matter later decays – re-releasing the sequestered CO2, trees sequester massive amounts of CO2 as wood. A lot of this happens in tropical rain forests, located near the equator. However, as global temperatures keep rising, some parts of the Earth’s equatorial area will become too hot for rain forest trees. Those trees will die, and then rot. Not only will sequestration decrease, but lots of sequestered CO2 will be released.
Yet another damaging positive feedback loop is already being seen in the melting of the arctic sea ice. The two polar icecaps are vast areas of white snow and ice. They reflect back into the atmosphere most of the sunlight that reaches them, meaning that the radiant heat carried by that sunlight goes back out into space. Even with the current level of global warming, more and more of the north polar icecap is melting in the summer months, exposing the much darker seawater underneath. That exposed seawater absorbs far more of the heat from sunlight, increasing the warming of the Arctic Ocean, which, in turn, further accelerates the melting of the polar icecap. The result of this cycle could soon be the total loss of the north polar icecap, with more warming and a huge increase in sea level.
At the South Pole, warming will also mean the melting of polar ice, which will expose the bare rock of Antarctica. Again, the result will be much more absorption of solar radiation, faster global warming, and more sea level rise.
Add all these feedback loops together, and at some point climate change will reach a “tipping point” – a point where temperature increases begin to accelerate. Once we reach that point, it will matter very little whether humanity has started making more serious efforts to reduce its GHG emissions, or even to sequester some existing emissions. It may well be “game over” for human civilization, and for many of the Earth’s plant and animal species.
Even after the tipping point, humans might be able, using drastic means, to reverse the course of climate change. Some people have proposed that we begin to engage in “geoengineering” – intentionally attempting to influence the Earth’s climate by, for example, putting large amount of reflective material into the polar upper atmosphere to replace the icecaps’ reflective effect. That, however, would come with its own huge risks. We would, in essence, be “playing God” with our own planet. We would be doing, however, without, the omniscience and omnipotence by which God would avoid unintended consequences. Moreover, the Earth is not like a computer game. There is no “Reset” button to punch if a particular experiment goes awry. It would be a “game” we’d be playing “for keeps,” and with all the planet’s life at stake.