Climate Tech 101
Climate tech is incredibly broad and easy to overcomplicate, so I wanted to write something to help simplify.
Enthusiastic newcomers often feel like they need to read a 4,000-page report or get a chemistry PhD to get started, which is not the case at all. It’s a lot easier and more fun than that!
There are a handful of important concepts others have taught me that help to approach climate tech. If you're new to climate tech, I hope you can use it as a jumping off point to go deeper wherever excites you!
The concepts are grouped by the themes below, each taking ~5-10 minutes to read:
- Part 1: a climate change primer (This one!)
- Part 2: reduce, remove, and retrofit
- Part 3: technologies that win
- Part 4: what to build
- The Breakout List for Climate
The climate tech community is truly awesome. Thank you to the countless people who have helped me get up to speed – I hope this post helps me start to be able to pay it forward in a small way.
Onward to Part 1.
Part 1: a climate change primer
Summary:
- The earth is warming
- We’re likely looking at 2-4°C of warming (from acceptable to crisis)
- Net-zero by 2050 is a great goal
- CO2 is most (but not all) of the problem
- ~50 billion tons of greenhouse gasses are emitted per year (and they’re not from where you’d think!)
- Energy is key — it takes 5,000 gigawatts to power the world today, and electricity will be a big part of the solution
The earth is warming
The best place to start is to define the problem.
The earth is warming. Carbon dioxide and other greenhouse gas levels are going up due to human activity, which is exerting a warming influence on the globe. It’s already warmed 1.1°C compared to pre-industrial levels, which we can measure pretty accurately.
From there, what will happen and what should we do about it?
Every 6 years hundreds of scientists look at tens of thousands of scientific papers to summarize our best understanding of climate change. It’s called the IPCC (Intergovernmental Panel on Climate Change) report, and the last one from 2021-23 just wrapped up. The next one won’t come until 2027.
You’ll hear about the IPCC report a lot. It’s treated as gospel in some circles, and is, at least, a solid benchmark. It’s generally objective, if not conservative, but press around the IPCC reports tends to take the science out of context and into doomerism. Check the summary to see for yourself.
What makes the IPCC report gospel? It represents generally good work on a super hard problem. Climate change is a complicated systems problem - you're modeling everything humans and nature do, and what we might do in the future, while considering carbon feedback loops that resolve over centuries. To acknowledge that uncertainty, the IPCC clearly probability-weights all claims and uses multiple scenarios to allow for uncertainty. It also uses great citations to support each claim.
On the other hand, the IPCC report is (fairly) criticized because it represents a watered-down political consensus. For example, “fossil fuels” aren’t named as the primary cause of global warming because Saudi Arabia blocked that obvious fact from being published; meat and dairy emissions aren’t mentioned as the huge problems that they are, due to lobbying from Brazil and Argentina.
So we start with this huge 4,000+ page scientific/political report, and we'll use it to answer our questions.
First, how much warmer will it get?
We’re likely looking at 2-4°C of warming
To set context, the 2015 Paris Climate Agreement (which 195 countries approved, including the U.S.) set a goal to hold the increase in the global average temperature to "well below 2°C above pre-industrial levels" and to pursue efforts to "limit the temperature increase to 1.5°C."
Some bad news: we’re going to miss the 1.5°C scenario, which was our stretch goal. Nobody in the climate space thinks it’s still possible, and even the IPCC report says it would require “massive and immediate cuts in greenhouse gas emissions”, which won’t happen. Sadly, we’re actually likely to overshoot 1.5°C by the early 2030s.
Some good news: we can still hit the <2°C goal. Also, the highest end of the range isn’t plausible. Historical trends put us at 5°C, but as renewable energy and other technologies have scaled, we're on a better track to ~3.5°C or better. We also narrowed our projections through better climate modeling. As a result, the highest emissions scenario is considered implausible, and the second highest scenario is unlikely, requiring continued regression.
Having said that, we have a lot of hard work ahead to get to a 2°C scenario – we aren't yet close:
On to the next question – what are the likely impacts of 2-4°C of warming?
From acceptable (2°C) to crisis (4°C)
At 4°C (7.2°F) of warming, there’s a very high risk of deadly extreme weather and higher mortality. In certain parts of the world, heat will kill, any day of the year (see above). Even the daily highs in the summer in Phoenix would be hot enough to kill a person.
By 2100, climate change could be 5x worse from a mortality perspective than COVID-19 was, recurring every single year. The ensuing global mortality, drought, famine, and conflict could cause refugee crises, geopolitical instability, and even armed conflict.
Seemingly small numbers like 4°C matter because:
- Small variations can have a big impact (e.g., 6°C colder is an ice age)
- Land heats faster than water, so we're impacted 1.5-2x more than the global average (there's a 25-50 year lag in ocean warming)
- Impact is not uniform and is larger at the extremes (e.g., in the 4°C scenario, the Arctic is likely to rise 7-11°C and low-lying island regions will be flooded)
At 2°C of warming, the situation is much better, but it still isn’t great. Some effects will be bad, like 98% of all coral bleaching and no ice covering the Arctic in the summer – but it's a realistic stretch goal. We have to fix what we can and adapt the rest.
Every amount we improve, the fewer people die and people are generally healthier and wealthier.
Net-zero by 2050 is a great goal
So, what should we do about it?
It depends on how much you value Miami not disappearing into the ocean!
Jokes aside, this is fundamentally a political question about trade-offs. If we move too slowly to decarbonize, then many people will die and suffer – including many in the developing world that didn’t cause this problem. If we move too quickly to decarbonize, then we aren’t generating the wealth and prosperity that lifts people around the world out of poverty and improves quality of life. Your individual politics and morals may cause you to care more or less about these sorts of things.
I like to stay out of politics. It's more fun that way. I'd rather focus on a goal.
Net-zero emissions by 2050 is a great goal. It's measurable, clear, achievable, and actionable. While it will be very hard, it's attainable without sacrificing quality of life. Many in climate tech are rallying around this target, and I'll use it as a goal in some of the rest of the posts.
Now that we've defined the problem at a high level, let's break it down into its sources.
CO2 is most (but not all) of the problem
When people talk about climate change, they often only think about carbon dioxide (CO2). However, that’s just a (mostly) useful simplification – methane is ~20-25% of the problem.
Most reports talk about "CO2e" (CO2 equivalents), which simplifies the problem. Methane (CH4) is the most important equivalent to focus on. It's ~25% of the problem, although that’s also a (mostly) useful simplification, since it stays in the atmosphere for much less time than carbon dioxide but is 50x more potent. The chemistry is complex, and there are multiple reasonable methodologies, so these simplifications are your friend!
Looking at the other greenhouse gases, water vapor is hugely important, but not something humans impact much. Other gasses we do impact like nitrous oxide (N2O), CFCs (certain refrigerants), and ozone (O3) are also important, though less so than CO2 or methane.
Some things help us. Snow “albedo”, the reflection of white snow, is important to deflect heat, and reduces as snow and ice melts. Clearing forests or reforestation can have a big effect on future warming. Reflective aerosols like dust and volcanic ash actually cool the planet. Crazy! I'll talk about that more in a future post.
~50 billion tons of greenhouse gasses are emitted per year (and they’re not from where you’d think!)
If you were like me, you might have thought that once we had electric cars and clean energy, we’d have solved climate change. Unfortunately, that's only a third of the problem.
We have a bias to things we see and touch. Electric cars and clean energy are only 31% of the problem (6% from passenger vehicles – a bit under half of the 14% on all transportation – and 25% from electricity generation).
Even ideas as seemingly mundane as changing our agriculture practices (such as changing diets, farming practices, or reducing food waste) could solve another 24% of the problem.
If cattle were a country, they’d emit nearly as much greenhouse gas as the entire United States.
Cows are ruminants, digesting food in multiple stomachs using a process of regurgitation – and cow burps alone are ~4% of the climate problem, let alone the ~9% of total emissions coming from cattle! Similarly, wet rice planting is not a necessary technique (we use controlled floods as a form of natural herbicide), and the water blocks oxygen from penetrating the soil, causing bacteria that emit methane to build up.
A similar story exists for manufacturing – we could solve another 21% of the problem through improvements in cement, steel, plastics, and other things we make.
Emissions are broadly spread throughout the economy.
Energy is key — it takes 5,000 gigawatts to power the world today, and electricity can be an even bigger part of the solution
Another way of looking at the same greenhouse gas data is that energy is almost always part of the problem.
The share of electricity in global final energy consumption is only ~20%, as energy comes in a lot of other forms than electricity today, such as gas for vehicles on the road or coal used to make steel. Most of those forms of energy are dirty. They're dirty because fossil fuels are insanely energy dense, and we currently need them to enable our modern lives.
While electricity is ~25% of the problem, it could be much more than 25% of the solution. We can use the same playbook we’ve seen with electric cars: great products that shift to electric power, eventually powered with clean electricity.
For example, if we want green steel, we should invest in breakthrough solution that use low-carbon energy sources such as hydrogen or clean electricity to replace traditional carbon-intensive processes.
If we want greener homes, we should invest in rooftop or utility solar and upgrade stoves, water heaters, and heating and cooling to electrical systems.
If we want sustainable flights, we should invest in things like biofuels or storing excess clean electricity as chemical energy in a “drop-in”/standard aviation fuel.
As we electrify more, we will increase electricity demand. More electricity will require more grid capacity and storage. I’ll get into the challenges and opportunities of energy in a later post.
I hope you enjoyed Part 1! For part 2, we’ll be introducing climate technology and how to think about it as an industry.