Field of Science

"How to Avoid a Climate Disaster", by Bill Gates. A fun read about a serious topic.

Bill Gates's book on climate change issues and solutions is exceptionally clear and simply written. Gates has an easy conversational style that makes the book a fun read, and he is clear-eyed about the problem and the solutions. He also stays away from politics, which makes the book a refreshingly apolitical read, especially in these times. Often Gates's interest as a hardcore nerd shows, for instance when he tours a geothermal energy plant on a family vacation. Gates is also modest; he recognizes well that the world might be skeptical to hear about climate change solutions from yet another billionaire who thinks technology can solve all our problems. The difference though is that that technology *can* contribute substantially to addressing climate change, and unlike almost any other rich person, Gates has shows that he has both the breadth of knowledge and - as shown by his vast philanthropy - the public commitment to tackle this huge challenge.

Gates starts by making the sheer scale of the problem clear: Firstly, there are 51 billion tons of carbon dioxide added to the atmosphere every year, and we need to reduce that number to zero. The useful metaphor he provides is of a bathtub which is full. Even if we reduce the flow of water, the bathtub will overflow at some point. The only two solutions are to turn off the tap and to drain the water.
Secondly, the sheer number of sources that contribute to this number make it very challenging to foresee how we can solve the problem - almost every activity we undertake in our daily life, from brushing our teeth (the plastic in the brush released GHGs when manufactured) to eating (the food we eat releases GHGs when grown with fertilizer and transported). One corollary of this realization is that whenever we analyze a new technology for energy or climate change, we have to undertake a cradle-to-grave lifecycle analysis to gauge whether the tradeoff it provides is truly positive; in my view, a lot of people have this blind spot when they make exaggerated claims about solar or wind power for instance.
Thirdly, we are not working on a static target; the world's population is not just growing but getting more and more energy-hungry, which means we have to work uphill against this increase in GHG production. These three problems might make us feel pessimistic or even hopeless, but as Gates says, there are many solutions in principle, and a few in practice that we can implement to address the problem.
Gates breaks down the problem and solution space mainly based on the sources of GHGs. Contrary to what most people think, the biggest source of GHGs is not electricity generation or transportation but making things like steel, cement, ammonia and plastics (as the table below shows, these contribute more than 30% of total GHG emissions). Replacing these essentials of modern civilization is a daunting problem, much harder than thinking of replacing electricity or transportation sources, in part because the making of things like steel and cement is limited by the constraints of basic chemistry. It also does not help that the use of these materials by growing economies is exponentially increasing. This leads Gates to say whenever any company approaches him with a promising clean energy solution, "What's your strategy for cement?". The third big source of GHGs is land use and food. Lastly, heating and cooling constitute the fourth big source of emissions. Part of our discussion about climate change needs to be pivoted away from the fashionable things like electric cars, solar and nuclear power towards "boring" things like steel and cement.



Gates tackles each of these four sources in turn and proposes solutions, some that exist in principle, others novel and experimental. A key figure to keep in mind is something called a Green Premium, which essentially refers to the extra price you would pay if you swapped out a fossil fuel source for one with clean energy; the smaller this number, the better the chance you have of making the replacement. For things like gasoline, it's not like solutions don't exist at all. There are some advanced biofuels and electrofuels (these split the carbon from the oxygen in CO2 using clean electricity), but the Green Premium for these is so high (200% in some cases) that they would be unaffordable for the average consumer. Biofuels made from crops also have the disadvantage that they take away land from food crops.
Gates discusses the standard renewable replacements, including wind and energy, and points out how the cost of these sources has reduced substantially in the last decade. But he doesn't dwell much on the fact that wind and solar still provide a very small percentage of total energy (2% for solar and 7% for wind in the United States). Interestingly, he also doesn't say much about the fact that both wind and solar energy involve the release of a substantial amount of GHGs when you consider their lifecycle, including materials like steel and cement that go into their construction. These sources are also intermittent and are limited by storage battery technology. Wind and solar are both good local solutions in big countries like the United States which have a lot of wind and sun in lots of places, but they are less attractive for other countries. For knowing more about the limitations of these renewables, I would recommend Vaclav Smil's book "Energy Myths and Realities".
Speaking of batteries, Gates has a really nice discussion of electric vehicles. He points out that pound for pound, the best lithium-ion batteries today pack 35 times less energy than gasoline. This makes any large-scale replacement of gas-powered vehicles by electric vehicles a distant dream. Doing some basic math, however, Gates neatly draws the line at cars and buses which travel relatively short distances between well-defined points and are light. He points out how it would be basically impossible to imagine heavy, long-distance trucks, planes and ships running on batteries; in those cases the battery weight would be prohibitive. Today it's also true that the average electric car would make you pay a few cents more for every mile driven compared to a gasoline-powered car; Gates calculates that unless gas goes above about $3 per gallon or so, electric cars would always remain more expensive.
Gates also discusses next-generation nuclear power (20% of total electricity in the United States), including a company he has funded called Terrapower which is designing a nuclear reactor that is intrinsically safe and can run on waste. The reactor hasn't been tested yet but looks promising. Nuclear power remains the single best chance we have to use *existing* technology that has high energy density and is zero carbon; as one of many facts illustrating how safe it is, you can get more radiation from eating a banana while sitting on the fence of a nuclear reactor plant than from the plant itself. Most fears of nuclear have been overblown, and air pollution from fossil fuel burning kills millions more than nuclear power ever has. In addition, compared to other energy transitions, the share of nuclear power grew remarkably fast. When Germany made the foolish decision to abandon nuclear power a decade back, they not only ended up paying the highest electricity prices of any European nation, but ironically ended up importing nuclear-generated electricity from France. Hopefully we will see sensible policy about this critical power source enacted soon.
Eating meat and deforestation also contributes to significant GHG emissions. Cows contribute about 4% of global emissions, literally by burping and farting methane; although methane has a shorter life than CO2, it has 28 times CO2's capacity to absorb heat. Gates is optimistic about countries shifting to plant-based and synthetic meat; as someone who has enjoyed an Impossible Burger occasionally, I think this shift will be possible but gradual. Emblematic of other solutions, it would also face huge political and social blowback as jobs from the meat industry including ranching and meat packing go away.
Heating and cooling also contribute to significantly to not just GHG emissions but electricity bills. Ironically, a warming world would lead to double trouble as people install more air conditioning, which leads to more electricity usage and emissions. This discussion in Gates's book is where the important role of local and federal government policy becomes clear. Replacing a gas or electric heater with a heat pump can reduce GHGs, but this change is not allowed in many homes by landlords and state laws. And asking for more electricity in your home from renewables is still expensive, leading to about a $10 per month hike in your electricity bill in many states.
Gates has a good discussion of two important remedies that aren't always part of the debate: adaptation and geoengineering. For some people adaptation means throwing up our hands, but for the poorest people in the world who would be almost certainly impacted by climate change even in the face of aggressive actions in the next few decades, it could be a lifesaver. Gates talks about drought-resistant wheat and flood-resistant rice (called "scuba" rice that becomes dormant when underwater) being already used in Africa and India. These solutions absolutely need to be researched and implemented. But a lot of adaptation also involves local measures like flood protection and smarter home design for cooling and heating; Gates points out mangroves as saving tens of billions of dollars from flooding already. Geoengineering is a politically fraught and technically untested solution, but I agree with Gates that as a stopgap solution it at least needs to be investigated. Perhaps the most general kind of geoengineering strategy under discussion is to seed the atmosphere with particles that would reflect back the sun's heat.
Finally, it's important realize that some solutions are technical while others are political. For instance, the problem of long-distance transmission of power from solar and wind farms could potentially be addressed by high-voltage power lines, but extending these across the country could cause significant disruption to communities and would involve thorny political deliberations. Gates talks about how important it is for the market, technology and government policy to work hand in hand to ensure good solutions for climate change; otherwise even if two of these work well and the third doesn't, solutions don't reach us. He has himself invested (and sometimes sunk) hundreds of millions of dollars on all kinds of companies and ventures dealing with adaptation and new energy replacements.
Part of the reason government policy becomes important is because of a single, almost cruel fact that is the elephant in the room - fossil fuels are stunning cheap, which is why an energy-hungry world has always embraced them. As Gates's simple calculation shows, a can of gasoline quite literally costs less than a can of soda. With other sources of energy competing against such a cheap source (for instance, battery technology will improve in the upcoming years, but it's virtually impossible to see it getting 35 times better as indicated above), governments will have to come up with smart schemes like a carbon tax and other incentives for consumers and corporations to move away from fossil fuels. The importance of government as well as companies investing in basic energy research cannot be overestimated; government especially can help industry overcome the "valley of death" between idea and deployment through low-interest loans and investment. Unfortunately, as a percentage of revenue, energy companies still spend a very small amount of money on R&D, much less than electronics or pharmaceutical companies for instance. This needs to change.
Ultimately though, in any market-driven economy, we as individuals can collectively bring about the biggest change by sending the right signals to both government and the market. In so far as doing this is concerned, there is really no substitute for being an informer consumer and citizen. In that sense Gates's book cannot come along at a better time.