Thinking about global warming recently, it occurred to me that there are basically five kinds of things that we have to do to reduce greenhouse gas emissions and have a stable climate for future generations to enjoy. Here's some information on California's greenhouse gas emissions by sector from the California Air Resources Board.
1. Green the Electrical Grid
We have to stop the use of fossil fuels such as coal and natural gas in the generation of electricity to have any hope of stopping global warming. Luckily, we have alternatives such as wind and solar. Even more luckily, it is possible to deploy energy storage systems such as lots of batteries, flywheels and pumping water up behind dams so that we can use energy sources that are generated intermittently whenever we need them. California has already made significant progress, getting 25% of its electricity from renewables in 2016 (this percentage excludes "large hydroelectric" which accounts for another 10% of California's electricity supply). State law requires this to increase to 50% by 2030, and we won't stop there if the current political climate holds. The U.S. average is lagging behind at 15% (which includes all hydroelectric power). I'm still waiting for He Who Shall Not Be Named to make America great again on environmental leadership (sarcasm).
2. Green the Transportation System
Oh boy, this one's going to be hard. All vehicles have to not be powered by refined fossil fuels such as gasoline and diesel. Instead, vehicles need to be powered by electricity and hydrogen. Luckily, electric cars have been getting much better and cheaper recently. Of course, we shouldn't just accept our car-drenched status quo because cars are still very energy intensive, kill a lot of people, and have other unfortunate impacts on our cities like making things less pleasant for people walking. Through urbanism, a major focus of this blog, we can put people's destinations closer to where they live and make it easier to get around using super-green transportation such as walking, bicycling and electrified public transit. I'm not just talking about land vehicles, by the way, ships and aircraft also have to convert to truly clean energy.
3. Phase Out Natural Gas Use in Buildings
Natural gas is a major source of fuel for power plants that generate electricity, but it is also a major source of fuel for heating things up in homes and businesses. Think of all of the stoves, water heaters and space heaters that are powered by gas in our homes, businesses and manufacturing processes. These need to be converted to run on that clean, renewable electricity described in Part 1, or on energy sources derived from said clean, renewable electricity, such as hydrogen.
4. Green Agriculture
Of course, as long as there are billions of people on Earth, we're going to need agriculture, but what we eat has a profound carbon footprint. Meat consumption is particularly problematic, particularly the consumption of ruminant animals such as cows and sheep, whose methane emissions make them the Hummers of food. Animals often eat food products that could be consumed by humans directly, and convert them inefficiently into edible calories, which uses more energy, water and land. So if we're going to get our greenhouse gas emissions down, we're going to have to eat less meat, and particularly fewer burgers and steaks than we do now. The more people there are on Earth, the harder this will be to accomplish. I don't think we all have to be vegetarians or vegans to pull this off, but we're going to have to at least be half-assed vegetarians sometimes.
5. Stop Habitat Loss
Natural habitats are filled with carbon sinks, such as trees and other plants that absorb greenhouse gases. Yet, we humans have a knack for destroying habitat, whether for agriculture, resource extraction or urbanization. Urbanism can play a helpful role here, with its advocacy of denser settlement patterns (which, by definition, use less land than typical American suburbia). As discussed in Part 4, agriculture is necessary, so to save land we're either going to have to eat less meat, stabilize the human population, or have vertical farms in buildings. Extracting fewer resources could be accomplished by more efforts at recycling so that we don't have to chop down as many trees or mine as many minerals.
So that's what we have to do. A detailed discussion of how to do it is a subject for another day. It won't be easy, but as usual, it helps to actually pay attention and try to do something, instead of pretending like this isn't happening. Everything we do individually and collectively, at every level of social and governmental organization, matters.