Climate change and the solutions needed to mitigate it represent an enormous challenge — its cause and effect permeate every facet of society. With such a broad challenge, it can be difficult to know where to start or how to make a difference. Most sources on the topic are either extremely dense or give you tidbits on climate-related topics while leaving out important context as to how it fits into the bigger picture. This series is a distillation of many sources and is meant to be high-level while going a few levels deeper into certain areas. I’ll also share resources throughout if you’d like to dive even deeper on a particular topic.
We’ll be covering what the scope and scale of this challenge looks like, what solutions might get us to a favorable outcome, some of the limitations of those solutions, the opportunities this challenge presents, and how we can think about allocating society’s resources to give us the best shot at an outcome that’s positive for society. We won’t cover all aspects of this complicated subject — no single source will — but hopefully it strikes the right balance of brevity and depth to give you a fuller understanding of our climate challenge and opportunity. Additionally, we’ll spend more time focusing on solutions and opportunities, rather than the negative impacts of climate change, as we need to act fast in implementing change.
In this first part, we’ll cover some orienting information, what a bad climate outcome means for society, where our emissions are coming from, limitations we’ll need to keep in mind when discussing solutions, as well as the scale needed to make a meaningful dent in our emissions.
While navigating the complexities of climate, it’s easy to get lost in the details. We must always remember some basic orienting goals — we want our planet to stop warming, and we need to reduce greenhouse gas emissions to do so.
97% of scientists agree our climate is warming due to an unprecedented amount of greenhouse gases being pumped into the atmosphere by humans. To avoid climate disaster, we need to prevent the average global temperature from increasing 2℃, or 3.6℉.
The main greenhouse gases are carbon dioxide, methane, nitrous oxide, and fluorinated gases. While methane, nitrous oxide, and fluorinated gases are much more potent than CO2 when it comes to heating, the main bulk of our emissions come from CO2. For that reason, emissions are often referred to in terms of their CO2 equivalent.
51 billion tons of CO2 equivalent are emitted each year and increasing. To stay below 2℃ and prevent a disastrous climate outcome, greenhouse gas emissions need to drop to net 0 emissions by 2050.
Ideally, we need to return to preindustrial levels of atmospheric CO2, which is about 280 parts per million (ppm); today, we are well above preindustrial levels, at 440 ppm.
The negative impact of the “business as usual” path
Change is difficult. Every bit of society depends on an energy and resource infrastructure, developed over the past two hundred years, that relies on emissions to function. Restructuring our society in a matter of decades will be difficult and costly, but the cost of not making that transition will be much higher. If we go down the “business as usual” path and don’t check rise in atmospheric greenhouse gases, we can expect rising average temperatures, drought and heat waves, lengthened and new growing seasons in some areas (a positive for certain locations), change in rain patterns, stronger and more frequent hurricanes, rising sea levels engulfing coastal cities, and melting global ice sheets (which act as heat reflectors when frozen, helping keep our climate cooler). All of these changes (along with potentially many more) will result in the collapse of certain resources, confrontation over those resources, destruction of infrastructure, mass migrations, death of humans, and the extinction of thousands of species.
Current estimates predict climate change will cause roughly the same amount of deaths per year as COVID-19 (14 deaths per 100,000 people) by mid-century, and even more by the end of the century if we continue at the rate we are going. Estimates also show in the next decade or two, that destruction caused by climate change will be economically equivalent to a COVID-sized pandemic every 10 years!
Main contributors of emissions
In order to understand how we can best tackle this challenge, it’s important to look at the main contributors of emissions, which span five categories.
As you can see above, while getting everyone to use Electric Vehicles (EVs) is important, won’t solve our climate problem alone. If we are going to get to 0 emissions, we will need to change the ways society operates.
The Green Premium
It will cost money to go green. There will be major economic implications as we change the way society makes things, moves things, grows things, stays warm, refrigerates things, and plugs in. Today, the clean way of doing things is more expensive than the carbon-emitting alternative in many cases — fossil fuels have a lot of cheap energy packed into them. The cost difference between doing something the dirty way and taking the clean route is called the green premium. The green premium is an important metric to keep in mind as you think about climate solutions, as the comparative cost to transition is one of the primary factors that dictates whether a given solution can scale.
There are many reasons why a clean alternative will have a green premium, but one main reason comes from the fact that many solutions today, or on the horizon, are nascent. The cost reduction that occurs through research, iteration cycles and scale, simply hasn’t taken place yet in many domains. Much like buying a computer in the 70s, many solutions are still expensive, clunky, and lack the infrastructure to scale. Fortunately, we know from experience — like what happened with microwaves, televisions, and computers — with investment over time, costs can be reduced dramatically. This is what happened with solar and wind power, which were quite expensive early on but now are amongst the cheapest forms of energy.
We still have a long way to go to get to a renewable energy economy. Below is the amount of energy produced by various sources globally.
Emissions by Country
Nearly 75 percent of global greenhouse gas emissions are generated by just 20 countries, with 7 countries responsible for more than half of emissions.
This means we can set targets for a small number of countries and have a big impact on emissions today. A major caveat is that countries like India and many in Africa are expected to have massive population growth and economic development. While the economic development is phenomenal for the many impoverished people living in those countries, and an outcome we should all want, there is the inconvenient truth that emissions from those countries will likely rise dramatically. Clearly, it would be unfair and inhumane to tell these countries “do not build and bring millions of people out of poverty, like developed nations have been doing for decades, to save the climate.”
This represents a big challenge, as developed countries will need to reduce their emissions while developing countries will likely increase their emissions over the next few decades. Hopefully, the investments we make in clean and renewable sources will reduce prices to a point that it makes economic sense, as with wind and solar, for these countries to build in a way that is both conscious of the climate and productive for their growth.
Getting familiar with the scale of solutions needed
It’s hard to wrap your head around which possible solutions will make a meaningful dent in the 51 billion tons of emissions we emit each year. One framework, provided by Bill Gates, poses 5 questions that act as filters as to whether a solution is viable or not.
How many emissions of the 51 billion tons can this reduce?
How much energy will it provide?
How much cement is this going to use? (Cement is a major emitter and used in many large scale projects needed to reduce emissions.)
How much space will this take up?
How much will it cost?
On the question of “how much energy will it provide?” It’s often hard to understand energy metrics if you’re not working with them regularly. When you are working with energy metrics regularly, you’ll often come across a watt, which is a unit of power, representing the rate of energy transfer. You calculate watts by dividing the number of joules transferred over the number of seconds; one watt equals one joule per second. You may also hear the unit watt-hours used regularly. Watt-hours represent the amount of energy generated or consumed when you run an x watts of power for y hours. If you run a 100 watt appliance for two hours, you’ve used 200 watt-hours. Your utility bill is likely in the form of kilowatt-hours, representing how much energy you used in a given month.
So when you hear terms like kilowatts or gigawatts, what does that mean in the context of power usage? Here are some back of the envelope calculations that can help you get oriented:
When you hear…..
Kilowatt — think power used at a “house” scale (kilo means 1,000)
Gigawatt — think power used at a “city” scale (giga means 1,000,000,000)
100+ Gigawatt — think power used at a “big country” scale
The world uses roughly 5,000 gigawatts of power at a given time.
The United States uses roughly 1,000 gigawatts.
These factors of scale will be important to keep in mind as we discuss climate solutions in following sections.
In this section we covered some basic orienting information as it relates to the challenge, what a bad climate outcome means for society, where our emissions are coming from, limitations we’ll need to keep in mind when discussing solutions, as well as the scale needed to make a meaningful dent in our emissions.
In the next section, we’ll talk about solutions that exist today, or are on the horizon, that have the potential to reduce emissions in a meaningful way. Throughout this exploration, I will try to highlight what the green premium for a given solution is, what factors are either preventing or promoting its scale at the moment, and what the overall impact on emissions would be if a given solution was scaled up.
 Hawken, Paul. Drawdown (p. xiv) // https://unece.org/challenge#:~:text=Methane%20is%20a%20powerful%20greenhouses,a%20greenhouse%20gas%20than%20CO2. http://www.bbc.co.uk/climate/evidence/nitrous_oxide.shtml#:~:text=Nitrous%20oxide%20makes%20up%20an,trapping%20heat%20than%20carbon%20dioxide https://www.epa.gov/ghgemissions/overview-greenhouse-gases
 Gates, Bill. How to Avoid a Climate Disaster (p. 35)
 Gates, Bill. How to Avoid a Climate Disaster (p. 34).
 Gates, Bill. How to Avoid a Climate Disaster (p. 70).
 Harvey, Hal; Orvis, Robbie; Rissman, Jeffrey. Designing Climate Solutions.
 Gates, Bill. How to Avoid a Climate Disaster (p. 56).