You've successfully subscribed to Scott Taylor
Great! Next, complete checkout for full access to Scott Taylor
Welcome back! You've successfully signed in.
Success! Your account is fully activated, you now have access to all content.
Success! Your billing info is updated.
Billing info update failed.

Thinking about climate change

Global warming is quite possibly the greatest challenge humanity has ever faced. We will need to remove around 1 trillion tonnes of CO2 by the end of the century. In this post I explore the fundamentals of the space, and explore potential solutions.

Scott Taylor
Scott Taylor
- 18 min read
Thinking about climate change

Global warming is quite possibly the greatest challenge we have ever faced.

A solution involves not only understanding most branches of science, but economics, politics and, more generally, human behaviour.

To date, even with our advanced technologies, planet earth's climate seems to remain beyond our control.

Last week I wrote about the fact that I’ve started to spend a lot of time thinking about some of the biggest challenges we face as humanity. My goal being to narrow these challenges and dedicate the next decade of my life toward realising some of the potential solutions.

To help me kickstart, I’m publicly writing a series of Amazon-style six-page memos that I will send to investors, philanthropists and potential co-founders with the ultimate goal of seeing if they’d like to partner, and tackle one of these challenges alongside me.

So how do I go about it? It won’t be easy, especially in fields where I have limited ‘applied’ or academic experience. I’m using these memos as a stepping stone toward real world experiments, hopefully validating some of my hypotheses.

Today, there’s an abundance of free information. What remains scarce is insight. Choose any non-trivial topic X, and a cursory Google search will give you evidence for both X and NOT (X).

So how do you find out what’s really true in the world of climate change?

That’s where thinking from first principles comes in. The basic idea behind this is to break down complicated problems into basic elements and then reassemble them from the ground up. I’ve found it to be one of the best ways to learn to think for myself, unlock creative potential, and move from linear to non-linear results.

Over the years there’s been so much fake news from vested interests, and well-meaning but conflicting reports about climate change. Couple this with the fact that attempting to solve it is hugely complex, with many interdependencies. Crafting a meaningful solution will mean not only exploring and understanding most branches of science, but economics, politics and, more generally, human behaviour.

By breaking each of these down to their basic elements it should help me understand them more thoroughly. Allowing me to build my own ground truths, and focus on the right stuff.

Why have I started with climate change?

Simple: time, and the lack of it.

Scientists are telling us that on current trends by the middle of this century, vast swathes of the world will be experiencing uninhabitable temperatures for weeks on end. In essence, making them no-go zones.  This means the next decade is make or break.

Thankfully, climate change is starting to gain some real attention.

People are increasingly paying attention to the fact that:

  1. We’re experiencing unprecedented lethal heat waves. It’s simply getting too hot and too humid for humans to be able to survive in many places.
  2. Our largest physical structures; ice caps, coral reefs, and rainforests are disappearing before our eyes. Sea levels are rising, literally making the habitable world smaller.
  3. There will be an estimated 200 million - 1 billion climate refugees in this century alone. This number of people on the move will be hugely destabilising.
  4. When you factor in the cost of the environmental damage caused by our continued use of fossil fuels,  it makes no economic sense to generate power in the way we have historically. The price of a solar panel, for example, has fallen 90 percent.

The climate sector has also grown dramatically over the last few years.

LowerCarbon Capital, Prime Impact & PaleBlueDot all launched. And several corporates have also announced their corporate venture funds tackling decarbonisation. Many more made net zero commitments.

Initiatives such as the Earthshot Prize are attracting some of the world’s smartest thinkers. Chamath Palihapitiya also announced the allocation of a “few billion” to solve the problem. He said recently that he believes the world’s first trillionaire will be someone involved in developing technologies to combat climate change.

When it comes to philanthropy, there is no one better versed than Bill Gates in understanding how to prioritise dollar impact to maximise lives improved or saved. He’s just announced a new book ‘How to Avoid a Climate Disaster: The Solutions We Have and the Breakthroughs We Need’.

So the foundation of a meaningful climate change ecosystem is already here.

This enables the “crazy ones”, or “the ones who see things different” to innovate, to think outside of the box, and to find the support and freedom to dedicate themselves to discovering solutions.

There’s going to be quite a few footnotes in this post. A lot of people who are much smarter than me have spent a lot of time figuring stuff out. I’m hoping that I’ll be able to stand on the shoulders of these giants. With a set of fresh eyes, and the ignorance that only someone new to the space can have.

Let’s see if I can connect some dots, and pull together a plan.

In the remainder of this post, I’m going to cover the basics of climate change, as well as how I’m thinking of approaching it — with scenario planning and probabilistic forecasting. Finally we’ll look at the most promising areas of research in 2020.

If you're interested, I'd recommend bookmarking the climate change six-pager —over the next couple of weeks I'll be working on it. With the goal of sending it as soon as possible.

What factors determine Earth’s climate?

The Royal Society has done a great job of introducing the topic, and much of what is written below is learned from their resources.

The Sun is the primary energy source for Earth’s climate.

Some of this sunlight is reflected back into space, predominantly by bright surfaces (e.g. ice and clouds) the rest is absorbed by the surface and the atmosphere.

Much of this absorbed solar energy is re-emitted as heat. The atmosphere in turn absorbs and re-radiates heat, some of which escapes to space. Any disturbance to this balance of incoming and outgoing energy affects the climate. Small changes in the output of energy from the Sun will change this balance.

If all the heat energy emitted from the surface passed through the atmosphere directly into space, Earth’s average surface temperature would be significantly colder than today.

Greenhouse gases in the atmosphere, including water vapour, carbon dioxide, methane, and nitrous oxide, act to make the surface much warmer than this because they absorb and emit heat energy in all directions, keeping Earth’s surface and lower atmosphere warm.

Without this greenhouse effect, life as we know it could not have evolved on our planet. Adding more greenhouse gases to the atmosphere makes it even more effective at preventing heat from escaping into space. When the energy leaving is less than the energy entering, Earth warms until a new balance is established.

Greenhouse gases emitted by human activities alter Earth’s energy balance and thus its climate. We affect climate by changing the nature of the land surfaces; for example, by clearing forests for farming. The emission of pollutants also affect the amount and type of particles in the atmosphere.

Scientists have determined that, when all human and natural factors are considered, Earth’s climate balance has been altered towards warming, with the biggest contributor being increases in CO2.

Human activities have added greenhouse gases to the atmosphere

The atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased significantly since the Industrial Revolution began.

In the case of carbon dioxide, the average concentration measured at the Mauna Loa Observatory in Hawaii has risen from 316 parts per million (ppm) in 1959 (the first full year of data available) to more than 411 ppm in 2019.

The same rates of increase have since been recorded at numerous other stations worldwide. Since preindustrial times, the atmospheric concentration of CO2 has increased by over 40%, methane has increased by more than 150%, and nitrous oxide has increased by roughly 20%.

More than half of the increase in CO2 has occurred since 1970. Increases in all three gases contribute to warming of Earth, with the increase in CO2 playing the largest role.

Scientists have examined greenhouse gases from the past — by examining air trapped inside ice in Antarctica, we now know that the CO2 concentration began to increase significantly in the 19th century. This is after it had stayed in the range of 260 - 280 ppm for the previous 10,000 years. Ice core records extending back 800,000 years show that during that time, CO2 concentrations remained within the range of 170 to 300 ppm throughout many “ice age” cycles - and no concentration above 300 ppm is seen in ice core records until the past 200 years.

This should already be setting off alarm bells. The change in the last 200 years compared to the past 800,000 years. And the impact from humans. Crazy.

Measurements of the forms of carbon in the modern atmosphere show a clear fingerprint of the addition of “old” carbon coming from the combustion of fossil fuels, as opposed to “newer” carbon coming from living systems.

Furthermore, it is known that human activities, excluding land use change, currently emit an estimated 10 billion tonnes of carbon each year, mostly by burning fossil fuels, which is more than enough to explain the observed increase in concentration.

These and other lines of evidence point conclusively to the fact that the elevated CO2 concentration in our atmosphere is the result of human activities.

Climate records show a warming trend

Estimating global average surface air temperature increase requires careful analysis of millions of measurements from around the world, including from land stations, ships, and satellites.

Despite the difficulty in collating the data, quite a few independent teams concluded separately (and unanimously) that global average surface air temperature has risen by about 1 degree celsius since 1900.

Although the record shows several pauses and accelerations in the increasing trend, each of the last four decades has been warmer than any other decade in the instrumental record since 1850.

Going back further (before thermometers) using proxies such as tree rings, ice cores and marine sediments, the data suggests that from the early 1980s to now, has been the warmest 40 year period in at least eight centuries.

Global temperature is rising towards peak temperatures last seen 5,000 to 10,000 years ago in the warmest part of our current interglacial period.

Many other impacts associated with the warming trend have become evident in recent years:

  • Arctic summer sea ice cover has shrunk dramatically.
  • The heat content of the ocean has increased.
  • Global average sea level has risen by approximately 16 cm since 1901, due both to the expansion of warmer ocean water and to the addition of melt waters from glaciers and ice sheets on land.
  • Warming and precipitation changes are altering the geographical ranges of many plant and animal species and the timing of their life cycles.
  • In addition to the effects on climate, some of the excess CO2 in the atmosphere is being taken up by the ocean, changing its chemical composition (causing ocean acidification).

Many complex processes shape our climate

Based just on the physics of the amount of energy that CO2 absorbs and emits, a doubling of atmospheric CO2 concentration from pre-industrial levels (up to about 560 ppm) would by itself cause a global average temperature increase of about 1 degree celsius.

In the overall climate system, however, things are more complex; warming leads to further effects that either amplify or diminish the initial warming.

The most important feedbacks involve various forms of water.

A warmer atmosphere generally contains more water vapour. Water vapour is a potent greenhouse gas, thus causing more warming; its short lifetime in the atmosphere keeps its increase largely in step with warming. Thus, water vapour is treated as an amplifier, and not a driver, of climate change.

Higher temperatures in the polar regions melt sea ice and reduce seasonal snow cover, exposing a darker ocean and land surface that can absorb more heat, causing further warming.

Another important but uncertain feedback concerns changes in clouds. Warming and increases in water vapour together may cause cloud cover to increase or decrease which can either amplify or dampen temperature change depending on the changes in the horizontal extent, altitude, and properties of clouds. The latest assessment of the science indicates that the overall net global effect of cloud changes is likely to be amplifying warming.

The ocean moderates climate change. The ocean is a huge heat reservoir, but it is difficult to heat its full depth because warm water tends to stay near the surface.

💡 Idea - could large jets well below the ocean surface circulate cooler water to the top? One to research for my memo.

The rate at which heat is transferred to the deep ocean is therefore slow; it varies from year to year and from decade to decade, and it helps to determine the pace of warming at the surface. Observations of the sub-surface ocean are limited prior to about 1970, but since then, warming of the upper 700m is readily apparent, and deeper warming is also clearly observed since about 1990.

Surface temperatures and rainfall in most regions vary greatly from the global average because of geographical location, in particular latitude and continental position. Both the average values of temperature, rainfall, and their extremes (which generally have the largest impacts on natural systems and human infrastructure), are also strongly affected by local patterns of winds.

Estimating the effects of feedback processes, the pace of the warming, and regional climate change requires the use of mathematical models of the atmosphere, ocean, land, and ice built upon established laws of physics and the latest understanding of the physical, chemical and biological processes affecting climate, and run on powerful computers.

Models vary in their projections of how much additional warming to expect (depending on the type of model and on assumptions used in simulating certain climate processes, particularly cloud formation and ocean mixing), but all such models agree that the overall net effect of feedbacks is to amplify warming.

Human activities are changing the climate

Data shows that most of the observed global warming over the past 50 years or so cannot be explained by natural causes and instead shows human activities have played a significant role.

In order to discern the human influence on climate, scientists must consider many natural variations that affect temperature, precipitation, and other aspects of climate from local to global scale, on timescales from days to decades and longer.

One natural variation is the El Niño Southern Oscillation, an irregular alternation between warming and cooling — lasting about two to seven years — in the equatorial Pacific Ocean that causes significant year-to-year regional and global shifts in temperature and rainfall patterns.

Volcanic eruptions also alter climate, in part increasing the amount of small aerosol particles in the stratosphere that reflect or absorb sunlight, leading to a short-term surface cooling lasting typically about two to three years. Over hundreds of thousands of years, slow, recurring variations in Earth’s orbit around the Sun, which alter the distribution of solar energy received by Earth, have been enough to trigger the ice age cycles of the past 800,000 years.

Fingerprinting is a powerful way of studying the causes of climate change. Different influences on climate lead to different patterns seen in climate records. This becomes obvious when scientists probe beyond changes in the average temperature of the planet and look more closely at geographical and temporal patterns of climate change. For example, an increase in the Sun’s energy output will lead to a very different pattern of temperature change (across Earth’s surface and vertically in the atmosphere) compared to that induced by an increase in CO2 concentration.

Observed atmospheric temperature changes show a fingerprint much closer to that of a long-term CO2 increase than to that of a fluctuating Sun. Scientists routinely test whether purely natural changes in the Sun, volcanic activity, or internal climate variability could plausibly explain the patterns of change they have observed in many different aspects of the climate system.

These analyses have shown that the observed climate changes of the past several decades cannot be explained just by natural factors.

How will climate change in the future?

Scientists have made major advances in the observations, theory, and modelling of Earth’s climate system, and these advances have enabled them to project future climate change with increasing confidence.

Nevertheless, several major issues make it impossible to give precise estimates of how global or regional temperature trends will evolve decade by decade into the future.

Firstly, we cannot predict how much CO2 human activities will emit, as this depends on factors such as how the global economy develops and how society’s production and consumption of energy changes in the coming decades.

Secondly, with current understanding of the complexities of how climate feedbacks operate, there is a range of possible outcomes, even for the particular scenario of CO2 emissions.

Finally, over timescales of a decade or so, natural variability can modulate the effects of an underlying trend in temperature.

Taken together, all model projections indicate that Earth will continue to warm considerably more over the next few decades to centuries. If there were no technological or policy changes to reduce emission trends from their current trajectory, then further globally-averaged warming of 2.6 to 4.8 degrees celsius in addition to that which has already occurred would be expected during the 21st century. Projecting what those ranges will mean for the climate experienced at any particular location is a challenging scientific problem, but estimates are continuing to improve as regional and local-scale models advance.

Scenario planning and probabilistic forecasting

Scenario planning

You may not expect this from someone who helps lead a team that tries to predict the future of financial markets — largely through probabilistic means in artificial intelligence and machine learning —  but I do believe that scenario planning can help frame the problem.

As mentioned, even though there have been major advances in the observations, theory, and modelling, uncertainty does remain. And it increases the more we explore the interactions between climatic and non-climatic trends and drivers.

Climate change adaptation requires balancing the unpredictability of specific climate change impacts with the need to take decisive timely action. Scenario planning is one way to shine some light. It involves developing and applying a small number of diverse, plausible stories about how the future will unfold.

Foreign Affairs gives a good summary on its origins:

This process of using alternative futures and pathways to test strategic choices grew out of post–World War II national security concerns, specifically the overwhelming uncertainty of the nuclear revolution. Nuclear weapons presented a novel problem. With the newfound ability to destroy each other as functioning societies in a matter of minutes or hours, the United States and the Soviet Union faced an unprecedented situation. And unprecedented situations are, by definition, uncertain. They lack any analogy to the past that would allow decision-makers to calculate the odds of possible outcomes. Unexpectedly, it was a RAND mathematician and physicist, Herman Kahn, who offered an answer. If the lived past could not shape strategy, perhaps the imagined future could. Kahn devoted himself to crafting scenarios that would prepare the United States for the future through what were essentially thought experiments.

Policymakers could use these scenarios as artificial ‘case histories’ and ‘historical anecdotes’ —thus making up for a lack of actual examples or meaningful data.

They would provide analogies where there were none.

The US National Park Service does a good job of summarising (PDF) the five types of scenarios for climate change (page 7).

Trading precision for accuracy

Scenarios overall stand in contrast to the conventional idea of prediction. When talking about climate change, scenarios are understood in two distinct ways, both of which are useful. One as a compromised form of prediction, and one as a radical alternative to it.

At one end of the spectrum are quantitative climate scenarios produced by climate scientists. These represent the range of uncertainty that exists about precise future climate conditions under climate change. They are derived from increasingly sophisticated modelling techniques.

At the other end of the spectrum are evocative stories and images created by diverse participants. These draw on a range of inputs that may include climate scenarios along with other information, ideas and imaginings.

These stories may be purely exploratory or openly normative - that is, they might examine values, ethics and goals. They are valuable for providing detailed images of what may emerge and what we can aim for.

The most recognisable form of scenario planning is a two-by-two matrix in which planners identify two critical uncertainties and, taking the extreme values of each, construct four possible future worlds. Regardless of the specific shape they take, rigorous scenario-planning exercises all involve identifying key uncertainties and then imagining how different combinations could yield situations that are vastly different from what mere extrapolation of the present would suggest.

The crucial characteristic of scenarios is their focus on possibility not probability. This is in contrast to conventional prediction based or risk management techniques such as forecasting, which provide a pinhole onto the future by extrapolating on current or assumed trends.

Scenarios trade precision for increased awareness of the future by presenting the expanse of possibilities, all grounded in plausibility. With this method, we’re not focused on the selection of the “most likely” scenario. Rather, the value comes from the breadth of possibilities.

This could get a little uncomfortable

Scenario planning techniques help open our minds to the future and hold it open — forcing us to confront the uncomfortable reality that in preparing for the future we must prepare for multiple outcomes. It helps to assess the effects of our decisions in different possible futures.

Scenario planning is also about unsettling other comfortable assumptions about the future. In the context of climate change adaptation, this involves exposing the unspoken norms underpinning the remit, purpose, possibilities and requirements of adaptation.

Probabilistic forecasting

Probabilistic forecasting tries to address that shortcoming. Forecasters see scenario planning as maddeningly vague or, worse, dangerously misleading. They not only point to the lack of consistent evidence to support the alleged benefits of scenario planning; they also argue that the compelling nature of a good story can trigger a host of biases. Such biases fuel irrationality, in part by tricking decision-makers into making basic statistical errors.

For example, even though a detailed narrative may seem more plausible than a sparse one, every contingent event decreases the likelihood that a given scenario will actually transpire. Nevertheless, people frequently confuse plausibility for probability, assigning greater likelihood to specific stories that have the ring of truth.

In contrast to scenario planning’s emphasis on imagination, forecasting tends to rely on calculation.

Deductive approaches use models or laws that describe the behaviour of a system to predict its future state. Inductive approaches do not require such understanding, merely enough data and the assumption that the future will in some way reflect the past. Increasingly, thanks to advances in artificial intelligence and machine learning, analysts use hybrid approaches.

Probabilistic naysayers will suggest that the chaotic nature of the climate system can limit prediction accuracy.

But that's really a myth.

Skeptical Science have a great, in-depth, answer for anyone who is interested in learning more. But the summary is:

Weather is chaotic because air is light, it has low friction and viscosity, it expands strongly when in contact with hot surfaces and it conducts heat poorly. Therefore weather is never in equilibrium and the wind always blows. The climate is mostly explained by equilibrium radiation physics, which puts the brakes on variations in global temperatures. Effects from weather, the Sun, volcanoes etc. currently only causes a small amount of chaotic behavior compared to the deterministic, predictable greenhouse gas forcing for the next 100 years"

Planning in practice

To be useful, any vision of the future must be connected to decisions in the present. Scholars and practitioners often claim that scenario planning and probabilistic forecasting are incompatible given their different assumptions and goals. In fact, they mesh well. A scenario planner’s conviction that the future is uncertain need not clash with a forecaster’s quest to translate uncertainty into risk. Rather, the challenge lies in understanding the limits of each method.

Most promising fields of research

Now it's getting interesting —new and innovative solutions. My end goal is to stand on the shoulders of these giants and come up with something novel that I can pitch to philanthropists, investors and smart thinkers. With the end goal of attracting capital and talent. Below I only touch upon the current approaches, in the six-page memo, I'll go into a lot more detail.

Direct air capture

Direct air capture (DAC) is a process of capturing CO2 directly from the ambient air (as opposed to capturing from point sources, such as a cement factory or biomass power plant) and generating a concentrated stream of CO2 for sequestration or utilisation. CO2 removal is achieved when ambient air makes contact with chemical media, typically an aqueous alkaline solvent or functionalised sorbents. These chemical media are subsequently stripped of CO2 through the application of energy (namely heat), resulting in a CO2 stream that can undergo dehydration and compression, while simultaneously regenerating the chemical media for reuse.

Carbon mineralisation

Some minerals naturally react with CO2, turning carbon from a gas into a solid. The process is commonly referred to as carbon mineralisation or enhanced weathering, and it naturally happens very slowly, over hundreds or thousands of years.

But scientists are figuring out how to speed up the carbon mineralisation process, especially by enhancing the exposure of these minerals to CO2 in the air or ocean. That could mean pumping alkaline spring water from underground to the surface where minerals can react with the air; moving air through large deposits of mine tailings — rocks left over from mining operations — that contain the right mineral composition; crushing or developing enzymes that chew up mineral deposits to increase their surface area; and finding ways to weather certain industrial byproducts, like fly ash, kiln dust or iron and steel slag.

Tree restoration

Planting billions of trees across the world is one of the biggest and cheapest ways of taking CO2 out of the atmosphere to tackle global warming. New research estimates that a worldwide planting programme could remove two-thirds of all the emissions from human activities that remain in the atmosphere today. “This new quantitative evaluation shows [forest] restoration isn’t just one of our climate change solutions, it is overwhelmingly the top one,” said Prof Tom Crowther at the Swiss university ETH Zürich, who led the research. “What blows my mind is the scale. I thought restoration would be in the top 10, but it is overwhelmingly more powerful than all of the other climate change solutions proposed.” - Source


Yep, you read that right. The vast surface area of certain types of fibrous asbestos, a class of carcinogenic compounds once heavily used in heat-resistant building materials, makes them particularly good at grabbing hold of the carbon dioxide molecules dissolved in rainwater or floating through the air.

The funding landscape

Investment has grown at almost 5x the rate of the overall global venture capital market between 2013-2019, or 84% compounded annually.

Azeem on 'Exponential View' gave a good summary:

  • We’re seeing an increasingly large number of founders start companies that tackle the “net zero” transition, in every one of the key sectors driving carbon emissions.
  • There is an emerging ecosystem developing. The players look somewhat different from the software venture ecosystem. While some generalist VC firms, like Sequoia and USV, are moving to invest in the sector—and more will—there is also a big batch of existing specialist investors, like Congruent & DBL, to draw upon.
  • Climate tech has many challenges. The technologies may be harder to develop or riskier than many internet plays. Getting early proofs of concept can be complex. Figuring out how to scale the business is harder than just dumping your App in the App store. All of these considerations will give rise to innovations in the ecosystem: new accelerators, new partnerships, new standard operating procedures and earlier corporate involvement.

Concluding remarks

If you made it this far, thank you! At ~5,000 words, I don't think many will.

With all of my six-page memos, they need to be grounded in fact. The building blocks need to be indisputable so that any logic and reasoning to follow can stand up to scrutiny.

I think it's safe to conclude that CO2 removal is urgently needed. And it's going to be a huge opportunity for those who can create an innovative solution that is economically robust, at scale. The UN's climate panel found that we'll need to remove between 100 billion - 1 trillion metric tons of CO2 from the air this century. Keeping warming below 2˚ C could necessitate sucking out 10 billion tons a year by 2050 and 20 billion annually by 2100, a study by the National Academies found.

For any solution that is economically scalable, there's basically infinite opportunity.

Cover photo by Dirk Spijkers on Unsplash.
Custom graphs & charts built using D3.js - thanks to Sergey for helping.
Thanks to Jonathan for reading through early drafts of this post.


Scott Taylor

Started and sold a few companies. My aim is to make sense of the world, constantly improve and become increasingly empathetic. Sharing what I learn along the way.