How To Avoid A Mass Extinction Tipping Point (Simply and Cheaply)

The Amazon from space (from PBS: NOVA)

One reason I wrote The Sky Woman (Flame Tree Press — September 6th) was to explore a scenario that I think is fairly likely: human population goes way down (mostly by choice — people choosing to have fewer children) and at the same time human beings do not manage to exert meaningful control or intentional influence on climate change.

The Sky Woman takes place in the 28th century, on an Earth where sharply reduced carbon emissions (due to massive depopulation and the collapse of global industry) have triggered a premature end to the Holocene interglacial. Ice sheets have advanced, taking out Northern Europe and other far-north and far-south latitudes.

This is an unlikely scenario in real life — the Holocene interglacial will probably extend for tens of thousands of years, even without considering the effects of human climate change. While orbital forcing will eventually return us another Ice Age, that could take as long as half a million years given our current output of CO₂ and methane.

What’s the most likely climate scenario within the next few centuries? We’re already experiencing increased temperatures, extreme weather patterns, drought, forest fires, and global sea level rise. Ocean biomass is decreased due to acidification and warming, and biomass of wild animals and insects is also sharply reduced (due to both climate change and habitat destruction). We’ll likely see more of the same for decades at least.

In a worst-case scenario, melting ice sheets, thawed tundra, and mass deforestation take us to a climate change tipping point, leading to “hothouse Earth.” This is the scenario of cli-fi disaster fiction: the ocean rises tens or hundreds of meters, coastal cities are underwater, and entire nations become uninhabitable due to heat, drought, and/or extreme weather. Worst of all, this kind of rapid-change scenario would likely be accompanied by a true mass extinction, where the vast majority of species on Earth would perish.

But this scenario isn’t inevitable. Humans, even when we act slowly, act at lightning speed compared to geological time.

Obstacles and Barriers To Action — Money and Emotions

Politicians financially beholden to oil and gas interests are the biggest obstacle to nations taking action and entering into global agreements to reduce greenhouse emissions. Despite that, every nation in the world except the United States has entered into the Paris Agreement to reduce emissions. And even within the United States, some states are unilaterally taking aggressive action against climate change.

Another barrier to action is emotional dysfunction. Attitudes regarding climate change range from hopeless nihilism to idiotic optimism. Politically the right tends toward head-in-the-sand denialism, while the left tends toward hand-wringing guilt in regards to personal carbon footprints (though plenty of environmentalists still fly in airplanes). Emotionality is understandable; the problem is big, complex, and has life-or-death consequences. But freaking out or ignoring the problem doesn’t help.

The following tenets might provide a basis for a pragmatic attitude toward climate change:

• Animal-driven climate change is natural. Burrowing worms once triggered a massive carbon dioxide release leading to climate change and mass extinction. We’re only the latest animal to have an exploding population and greenhouse-gas-releasing lifestyle. We’re also the first species who might be able to do something about it.
• We are evolutionarily optimized as a species, global civilization, and member of an interdependent ecosystem (that also includes pollinators, other mammals, fish, etc.) for an interglacial climate. Anything other than an interglacial climate (such as a “hothouse” or “snowball” climate), while perfectly natural, would obliterate life as we know and prefer it.
• Climate change is influenceable. I use influenceable instead of fixable, because there are chaotic factors, unknown variables, and tipping points outside of our control. But as we’re obviously already influencing climate change, it’s reasonable to think we can influence climate change with intentionality.

What Kind of Geoengineering?

Two common attitudes toward geoengineering (deliberate and large scale intervention into the Earth’s climate system) are:

• Overoptimistic idealism; the expectation that Silicon Valley and/or other white knight technology initiatives will scoop up excess carbon just like that, and global warming will be “solved.”
• Pessimistic skepticism; the idea that technology can’t play a meaningful role in carbon sequestration, and that mucking about with geoengineering will invariably lead to Sorcerer’s-Apprentice-style unintended consequences and/or increased socioeconomic inequity.

For some approaches to geoengineering, skepticism is warranted. Injecting smog into the upper atmosphere to reduce solar radiation could cool the planet a bit, but the cost to do so on a large enough scale to have a significant effect would be insanely expensive (US$2-5 trillion). And no carbon would be sequestered with this approach.

On the other hand, we can’t sharply reducing emissions without technological innovation in the fields of energy production, transportation, agriculture, etc.

A comprehensive, pragmatic approach to achieving a negative carbon balance might look something like this:

• A combination of best practices and technological innovation to reduce emissions in fuel-intensive industries, like shipping.
• Provide economic incentives to reduce deforestation, especially in the Amazon.
• A shift to 90%+ renewable energy production by mid-century or sooner, as is being spearheaded in some Northern European and Central American countries.
• Intensive, large-scale reforestation projects, such as this one in the Amazon, Kenya’s Green Belt Movement, South Korea’s postwar reforestation, and China’s Great Green Wall (not without its problems).
• Preserving and restoring wetlands, peatlands, bogs, and swamps, which act as huge carbon sinks.

The bottom line is that we need to remove about 700 gigatonnes of carbon dioxide from the atmosphere before the end of the century, in a way that nations can afford. Land management and regreening projects provide the most bang for the buck. With the sickening exception of the current U.S. administration, most countries are headed in the right direction.

On a personal level, we can reduce energy consumption, choose renewable energy sources, support reforestation and conservation efforts, and fly on airplanes less. But most importantly, we can choose political leaders who understand the science and severity of climate change, and are willing to implement plans to aggressively reduce emissions.

Generating “Moon Shot” Enthusiasm

I can’t think of any technological/social/political/cultural goal more important than sequestering enough carbon dioxide to avoid an irreversible climate change tipping point. Asteroid detection and deflection ranks pretty high too, but as I learned at a recent WorldCon panel, 99%+ of the large asteroids that could potentially impact the Earth are already being carefully tracked.

It’s harder to get excited and motivated about carbon sequestration than it is to get excited about more tangible scientific goals, like SETI, space exploration, or establishing human bases and colonies throughout the solar system.

Harder, but not impossible. The stakes are high, the progress is measurable, and the reward is literally saving the vast majority of life on Earth (jellyfish, algae, and cockroaches will probably be fine regardless). Progress trackers like this one are a good start. More news coverage about major greening projects can raise funds, generate enthusiasm, and fight hopelessness and denial.

In The Sky Woman, those with foresight build and escape to huge ringstation habitats the orbit the Earth, avoiding environmental disaster and the collapse of civilization. It’s a tempting fantasy, but exceedingly unlikely due to cost and technical hurdles. What is within our collective grasp is planting more trees, protecting and preserving wild habitats that act as carbon sinks, burning less wood and coal, and building cleaner machines.