How to save the planet

Bill Gates has written a book titled How to Avoid a Climate Disaster. Anyone who is concerned about the climate crisis will find it fascinating.

He starts by saying that there are two numbers we need to know:

(a) We are currently emitting about 51 billion tons of greenhouse gases every year. Every tonne of these gases makes the earth a little hotter.

(b) Our target is to add zero greenhouse gases (“net zero”) to the atmosphere.

“Net zero” requires some explanation. No matter how hard we try, we will not be able to reduce greenhouse gas emissions to zero. We can reduce some emissions, for example by producing electric power without burning fossil fuels, by using non-fossil electricity to power cars, homes and factories.

However, growing food crops with chemical fertilizers produces carbon emissions, and we will never stop doing this. Carbon emissions which we can’t avoid will have to be removed from the atmosphere so that our net emission is zero.

Gates explains that the following human activities all contribute to emissions:

Making things (particularly making steel and cement) contributes 31%

Electric power contributes 27%

Growing food contributes 19%

Transportation contributes 16%

Heating, cooling, and refrigeration contribute 7%.

Gates uses the concept of green premiums. Many human activities produce emissions, but in many cases, the same activity can be performed without producing emissions; however, there is almost always a “green premium” or increase in cost associated with avoiding emissions. For example:

“The average retail price for a gallon of jet fuel in the United States over the past few years is $2.22. Advance biofuels for jets, to the extent they’re available, cost on average $5.35 per gallon. The green premium for zero carbon fuel, then, is the difference between these two prices, which is $3.13. That’s a premium of more than 140%.” (Page 59)

In some cases the emissions of an activity (like making cement) cannot be avoided with present technology; in that case, the “green premium” is the additional cost of removing the emissions from the atmosphere (while making the cement). Removing emissions (direct air capture, DAC) at present costs about $200 per tonne of CO2.

Gates mentions that although electric power accounts for only 27% of emissions, producing electric power without emissions is the most important part of the solution, as many emissions from cars, factories, and homes can be eliminated if these are powered by non-fossil electricity .

Certain things have a very low green premium. In this case, policy changes are required. If a particular company produces a product in a manner which avoids emissions (requiring it to spend a small green premium), policy should prevent that company from being undercut by competitors who are still producing emissions. The most effective way to do this is to put a price on carbon emissions, which can be done by taxing carbon emissions.

Certain things have a very high green premium. In such cases, research is necessary to figure out how to reduce the green premium. Green premiums need to become low enough so that companies in middle income countries can go green; it won’t be enough if only rich countries go green.

Gates discusses the difficulty of producing continuous electric power with zero emissions. During the daytime, solar power costs only about 5 cents per kWh. However, if that electrical energy is stored in a battery and used at night, it will cost over 15 cents per kWh. This is too expensive compared to electrical power from fossil fuels; that’s why utilities that own solar power assets usually use gas burning power plants for backup power. However, burning gas produces emissions.

Gates argues that at present, nuclear power is the only continuous non-fossil power which can be scaled up. Solar and wind are intermittent, and depend on fossil fuel backup; hydroelectric power is continuous, but requires sacrificing too much land. He mentions that he has invested in a company which is working on a next generation nuclear plant with energy storage. Nuclear energy can be stored as heat; at night, the stored heat can generate zero emission backup power when solar power is not available.

Gates acknowledges that Chernobyl and Fukushima were serious accidents, but argues that we should have responded to these accidents by building better (safer) nuclear plants, rather than by giving up on nuclear energy. Electric power demand will grow very fast in lower income countries as more and more people buy refrigerators, air conditioners, and vehicles (remember, we want them to buy electric vehicles); so we must make zero emission electric power affordable.

Gates discusses how making things (31% of total emissions at present) can be done with zero emissions. He points out that in some manufacturing processes, fossil fuel energy can be replaced with zero-carbon electricity. However, no one has figured out how to make steel or cement without emissions, as the chemical reactions which produce these produce CO2.

To make zero emission cement and steel, the carbon emissions of the process have to be captured, which leads to high green premiums: 16-29% for steel, and 75-140% for cement. In poor countries, which are urbanizing, there will be huge demand for steel and cement; we need to figure out how to lower the green premium for these goods.

Gates discusses how growing food (19% of total emissions at present) can be done with lower emissions. A huge proportion of the emissions come from raising animals for meat and dairy. These emissions are likely to grow quickly as people in low-income countries experience rising incomes and eat meat more frequently. Beef is particularly problematic, as cattle consume 6 calories of feed to produce 1 calorie of beef.

He mentions that the best option is to develop plant-based meat substitutes which taste like the real thing and are cheaper than the real thing (ie, with a negative green premium). This is going to take research. The goal is to reduce the world’s demand for meat from animals, and create demand for plant-based meat substitutes.

About half of the nitrogen in chemical fertilizers is not absorbed by plants, and eventually becomes nitrous oxide — a greenhouse gas. Unfortunately, feeding the planet is not possible without chemical fertilizer. Research is required to find alternatives to the present chemical fertilizers which produce fewer emissions; obviously the demand for food will only grow as population and incomes grow.

Some have proposed tree-planting on a massive scale to absorb carbon emissions, but Gates explains why this simply won’t work. Our emissions are so vast, one would have to plant trees on 24 million square miles (roughly half the landmass of the world) just to absorb the lifetime emissions of the present population of the United States.

Gates discusses how transportation (16% of total emissions at present) can be done with lower emissions. Passenger cars and city buses are easy; the green premium of an electric car is low. However, electric cars are only zero emission if electric power is zero emission. The problem is with long distance transports: Trucks which burn diesel, ships which burn bunker fuel, and planes which burn jet fuel.

All three of these need a large amount of energy for a long trip; a battery to store so much energy would make the vehicle too heavy (reducing its cargo or passenger carrying capacity). So we won’t be able to power these transports with batteries. Advanced bio-fuels can substitute for these fuels. These have high green premiums: 103% to replace diesel, 141% to replace jet fuel, and 326% to replace bunker fuel.

Gates discusses how heating and cooling (9% of emissions) can be accomplished with fewer emissions. Fortunately this is simpler; much air conditioning is already electric, and can be made zero emission by moving to zero emission electric power. At present, heating is mostly dependent on burning fossil fuels. However, heating with an electric heat pump (like the heat pump which cools a refrigerator) is often cheaper than burning fossil fuels to heat a building (a negative green premium). This will change quickly if building owners can be given an incentive to re-fit their buildings; this is just a policy change.

Gates argues strongly that the right government policies are critical. The single most important step is simply to put a price (ie, a tax) on carbon emissions. The right price on emissions will make many green premiums negative. This will motivate every person and every company to reduce their emissions.

Funding for research to reduce green premiums is critical. However the right policies will only be enacted by elected officials if the public demands them. So the most important thing every person can do to avoid a climate disaster is to become involved in their community, and to demand the right policies.

Kazi Zahin Hasan is a businessman living in Dhaka.

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