Geoengineering Alone Cannot Save The World
We need more than clever engineering to prevent climate disaster.
In the early days the yearly rise could hardly be seen. The annual cycle of carbon dioxide — the summer drop as forests bloom and soak up carbon, the winter jump as leaves wilt and rot — dominated the measurements. But the rise was there, nonetheless.
By the 1960s the cumulative effect of our global carbon dioxide output was becoming harder to miss. Now, sixty years later, the trend is obvious to all but the most unwilling to look. Over those six decades carbon dioxide levels have increased by almost a third, and every year the annual rise has grown larger and larger.
This is not a natural process. It is one almost entirely man made, thanks to our industrial, carbon spewing civilization. Every year we put tens of billions of tonnes of carbon dioxide into the atmosphere. We take almost nothing out.
The result is inevitable. The more carbon dioxide in the air, the more heat the planet retains from the Sun. Year by year this heat adds up, slowly warming the planet.
The consequences will be severe. We risk turning vast swathes of the planet to desert, disrupting vital weather systems that bring water to billions, and unleashing vast floods as the polar ice sheets melt. None of this will be good.
Since the threat has become clear, scientists have urged governments to promote carbon reduction strategies. Instead of burning fossil fuels, nations should rely on cleaner sources — wind, solar or nuclear. Instead of dirty oil powered cars, we need to move to electric vehicles. All this is well known.
But so far, as the ever increasing carbon dioxide levels show, this has not had much impact. Even worse, the full extent of the warming has not yet been felt. If we stopped emitting carbon dioxide tomorrow, global temperatures would still keep on rising for centuries, thanks to all the carbon dioxide already in the air.
Hence the desire for scientists to find a new solution. Some are turning to the idea of geoengineering — artificially manipulating the climate to our favour. Those who argue for this approach point out we are already altering the climate by adding carbon dioxide. Why not, then, actively take steps to balance that out?
Several possible approaches exist. We could mimic volcanic eruptions and pump large amounts of reflective particles or gases into the upper atmosphere. The result would be to reduce how much solar heat the planet gets, thus cooling things down, as the huge eruption of Mount Pinatubo did throughout the early 1990s.
Others call for seeding the ocean with iron, creating huge phytoplankton blooms that would soak up large amounts of carbon dioxide. As the bloom dies off, the carbon would fall to the ocean floor, safely locked away. Or we could more actively suck carbon dioxide out of the air, either with machinery or large scale forest planting.
Such approaches might buy us time, but they present a lot of risks. We’re not at all sure how well they might work — even no-brainer ideas like planting forests may not actually reduce carbon levels all that much. And even if they do work, there’s a risk of unintended consequences.
The global climate is a complicated system. If, for example, we add reflective particles to the upper atmosphere, we might accidentally unleash climate chaos. Mount Pinatubo added tonnes of sulphuric acid to the stratosphere, cooling the Earth by half a degree. But the eruption also damaged the ozone layer, and may have caused storms around the planet.
More worrying is the fact that geoengineering needs to be an ongoing process. If we start actively intervening and managing the global climate, we need to make sure we can keep doing so for centuries. A sudden stop could be catastrophic — if we artificially keep the world cool for decades and then abandon the project, a sudden temperature rise would follow.
All this means geoengineering is not a viable alternative to cutting carbon emissions. Doing both may be the best option — but the risk remains that removing the urgency of global warming will slow efforts to reduce pollution. If they do slow, or even reverse, geoengineering cannot save the world. It can only delay an inevitable reckoning.
The EmDrive has been a favourite of science writers for a while. The proposed spacecraft engine violates the laws of physics, and has no realistic explanation of how it might work. Even so, various experiments have seemed to show it does actually produce thrust, and that it could be a breakthrough for long distance space travel.
Those experiments were promising enough to attract funding from NASA and DARPA for further research. What has long remained unclear was how reliable those experiments were. Without rigorous studies it was impossible to tell if the thrust was actually generated by the engine, or from some other effect.
Now a group of physicists at Dresden University has concluded that the results of every known EmDrive experiment can be explained by standard physics. The EmDrive, in other words, is a dud.
A recent paper suggests that the modern Amazonian rainforest was created by the meteorite impact that wiped out the dinosaurs. That devastating event would have killed off many of the large creatures that once roamed the area, allowing large trees to grow and form the modern rainforests.
So much reporting around health, science and space exploration is unrealistic, hyperbolic and misleading. These are complicated topics, and there are often no easy or straight forward answers. Instead what is needed is analysis, discussion and an exploration of the possible ways forward.
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