The short answer: Probably not.

The long answer: Probably not, but we don’t know what we don’t know. And currently, we don’t know a lot.

Let’s first clarify what is existential risk.

It is a risk that causes humanity to go extinct, in the same way that dinosaurs did. This is not equivalent to past world wars, epidemics and pandemics or even civilization collapses. It is the entirety of humans wiped out or with no chance of the future, or a very bleak future, like the ones present in dystopian fictions such as 1984.

In his recent book The Precipice, Toby Ord outlines the potential existential risks that humans are facing in the 21st century, which amounts to an odd of 1 in 6 that humankind will go extinct, the equivalent of a roll of a dice.

Here’s a breakdown of the probability we will go extinct, from different causes:

• Risks from natural physical catastrophes (total of risks from asteroids, supervolcanoes, etc.) : 1 in 10,000
• Risk from naturally arising pandemics: 1 in 10,000
• Risk from a nuclear war: 1 in 1,000
• Risk from Climate change: 1 in 1,000
• Risk from an Engineered pandemics: 1 in 30
• Risk from unaligned General Artificial Intelligence: 1 in 10
• Unforeseen anthropogenic risks: 1 in 30

Overall risks: 1 in 6

For a detailed analysis, you can get the book here. Link not affiliated, I just really like the book.

Based on this analysis, which summarizes roughly15 years of research, climate change is not our biggest concerns. If you are really worried about humans going extinct, you should be working on preventing unaligned general AI (100 times more important), or preventing an engineered pandemic (30 times more important).

But why is climate change so low on the list? Isn’t it one of the most immediate danger there is in the 21st century? Isn’t there disastrous consequences if we don’t act now?

Yes, yes and yes. But there is more we need to unpack.

Will this dystopian be humanity future?

Why Climate change is (probably) not a existential risk

Firstly, Toby Ord still acknowledges there is a 1 in 1000 chances of climate change being an existential risks, so the odds are not 0. But it is low enough to be negligible.

While Ord did not go indepth in his analysis, in this highly detailed document, researcher John Halstead discusses all the potential ways that a climate change can be an existential risk, and estimate the likelihood of it happening. Using the Equilibrium climate sensitivity and Earth system sensitivity measure, he examines key tipping points, such as the permafrost carbon release and clathrate methane release, effect of mass extinction, ocean acidification, heat stress, water stress, crop reduction and sea level rise.

In all scenarios related to climate system feedback loops and tipping points, especially the ones that are irreversible for millennia, the increase in temperature is actually negligible compared to human sources (for instance, permafrost would cause only an increase in 0.42 degrees Celsius by 2300 at the current rate) or unlikely to happen based on our knowledge of what happens in previous climate eras (eg. although Methane Clathrate could release 50 Gigaton of carbon and cause a 1.75 degree Celsius increase, it would probably take centuries to millennia, during which humans could have enough time to adapt and mitigate the effect).

https://cdn-images-1.medium.com/max/800/0*sm8KIIchSd1hri1j

Summary of key feedback loops and tipping points. Source: IPCC, Climate Change: The Physical Science Basis, 526.

Other indirect threats for existential threats were also considered, but found to be unlikely. Species have adapted to much higher temperature change in the past, and paleology has suggested that the primary cause of mass extinctions were often due to volcanic eruption rather than only the increase in CO2. Sea level rise will increase by 1 meter by the end of the millennia, which can be managed and adapted. Similarly, heat stress will be more often, but there is already adaptations like air-conditioning, and water stress can be fixed by desalination. Meanwhile, crops yields, which was modeled by the IPCC model at 5 degree of warming, would generally range from -20% to +10% with adaptation. Furthermore, we can expect increase in yield thanks to technology such as gene editing, improvement in storage, logistics and transportations to reduce food waste, and so on.

https://cdn-images-1.medium.com/max/800/0*PrVEY-HhtT0-1RUp

Crop yield change prediction by IPCC. Source: IPCC, Climate Change 2014: Impacts, Adaptation, and Vulnerability: Summary for Policymakers (Cambridge University Press, 2014), 498.

It’s not all black and white

This is not to say climate change won’t be worrisome. It can be 5 times more deadly than the COVID-19 by 2100, due to heat waves, droughts and floods, not to mention creating hundreds of thousands of climate refugees.

By 2060, climate change could be just as deadly as COVID-19, and by 2100 it could be five times as deadly. — Bill Gates

And that’s not to say that it cannot cause an extinction either. Firstly, there is a lot of uncertainties in all climate models, especially for the tail-risk i.e. if we reach an increase of 6 degrees or more. While an increase of 6-degree sounds like a distant future, if we reach 700 ppm CO2 in the air (which is where we are currently headed based on current policy), there is a 1-in-10 chance we might have a warming of 6 degree Celsius.

Moreover, even if climate change would not cause an existential risk from the physical science side, it can cause massive indirect risks, such as mass migrations, political conflicts and riots. Thus, climate change might not cause humanity to go extinct directly, but the political unrest associated with and accelerated by climate change may cause a nuclear war that wipes out humanities. Or it can lead to national hostility that prevents cooperation to focus on other important risks such as engineered pandemics or unaligned AI.

Thus, climate change may not be an existential risk, but it should be considered as an existential risk factor: its presence may not cause direct human extinction, but increases the chance of humanity going extinct. And that is scary to think about.

What to do about it

Besides the obvious answer of rapid decarbonization, rapid electrification, technology and development for carbon sequestration and storage method, and a whole other that I have listed here, research is especially lacking when it comes to the tail-risk of climate sensitivity, and there is still uncertainty to a lot of the key feedback loops. Torby Ord has listed in his book potential research areas that might be useful to look into:

• Possibilities of a Runaway Greenhouse Effect or Moist Greenhouse Effect
• Understanding of Permafrost And Methane Clathrate Feedbacks
• Understanding of Cloud Feedbacks
• Characterize Right-hand Tail Of Climate Sensitivity
• Improve our understanding of extreme warming
• Investing in Food Substitutes in case of extreme and lasting reduction in world’s ability to supply food

If there’s something the pandemic has taught us, it is both how fragile our systems are, and how we are dependent on forces of natures. If humans want to continue being part of the natural systems, we need to respect, learn from and work in tandem with them. If not, the price we pay might be our entire species existence.

If you want to learn more about this topic, this document and Climate Shock are an excellent start.