Amit's Thoughts: environment

From Amit’s Thoughts

Heat needed to melt ice #

I knew that melting ice takes heat, but didn't have a good sense for how much. I decided to calculate it.

1. Specific heat tells you how much heat it takes to increase temperature. For water, it's around 4.2 joules per gram of water to raise the temperature by +1°C.
2. Latent heat (of fusion) tells you how much heat it takes to turn solid into liquid, while not changing temperature. For ice→water, it's 334 joules per gram of water.

So we have two different processes: water to hotter water, and ice to water. How do they compare? Let's divide 334 J/g/°C ÷ 4.2 J/g = 79.5 °C.

That means the same amount of heat can do either:

1. Melt ice.
2. Raise water temperature by 79.5°C (143°F).

Yow!

That's much higher than I expected. Did I do the calculation wrong? I checked specific heat and latent heat again, but I can't see anything wrong with the calculation.

Now imagine what happens with climate change. If you add heat to a system, and there's ice around, it will melt the ice. But if there's no ice around, that same amount of heat will increase the temperature by 79.5°C (143°F). eeek!!

(please tell me I did the calculation wrong, because those numbers are scary)

Labels: environment

We need infinite energy #

[Warning: my thoughts on this topic are still not entirely clear. I sat on this post for a week but I couldn't find better words, so I decided to post anyway.]

When I think about being “green”, I think of three things:

1. Clean: solar, wind, wave energy instead of coal, oil, and sometimes nuclear. Part of this is to reduce pollution, but lately it's about reducing CO₂ released into the atmosphere.
2. Sustainability: renewable energy, better agricultural practices, and sometimes population reduction/stability. This is to avoid depleting resources.
3. Conservation (mostly of energy): less driving, less air travel, less lighting, less water, less energy. This is to reduce the impact of our activities on the planet.

I think all of these could use refinement.

I'm a big fan of Clean. Pollution in general is getting too little attention these days, and CO₂ gets too much. CO₂ is not a poison; it's a good gas to have. Our problem is that we're way out of balance. We're producing far more than we use, so it's building up in the atmosphere. We need to get back into balance, but that doesn't mean zero. Pollution on the other hand we should be at zero. But it doesn't need to be zero production; it's okay to produce if you can clean it up. For example, algae, fungi, and bacteria can be used to clean up some types of pollution, and titanium dioxide can do wonders. Here again balance is the key. Produce as much as is used, and we're good. That's different from saying produce zero.

I'm a fan of Sustainability but I think it's secondary to, and a consequence of, balance. I think depleting non-renewable resources is fine, as long as we do it knowing we're using it up, and we start coming up with a sustainable solution. We might decide to use oil, but deciding not to use it because we're going to use it up is not a compelling reason. Not having any oil and not using any oil are essentially the same. I think for now we should continue using oil, especially for waxes, lubricants, and biodegradable plastics.

I'm less of a fan of energy Conservation, in part because I think it addresses the wrong issue. (Raw material conservation is a separate issue.) The problem isn't turning the lights on. The problem is the impact that causes, because the electricity is generated in ways that pollute or produce CO₂. Do you turn off your solar-powered yard lights when you don't need them? Doesn't it sound silly? Turning off your incandescent bulb powered by a wind farm seems almost as silly. Solar, wind, and wave energy are abundant—in fact, literally tons of photons fall on the Earth every hour. And if we don't use that energy, it's lost. If we had abundant clean, cheap energy, would we still feel bad about using incandescent lights? I think we would, because we're trained to, but we shouldn't. There are still good reasons to use less energy, but they're about cost rather than environment.

Historically, asking people to switch to a worse lifestyle at lower cost (public transit in suburbs, abstaining from sex, eating boring food, not going on vacations, using unpleasant lighting, etc.) doesn't seem to be as effective as asking people to switch to a better lifestyle at higher cost. The EV1 and original Insight were “sacrifice” cars. You had to give something up (range, comfort, size), but you could feel good about sacrificing for the sake of the environment. The Prius is quite different. It is comfortable, is roomy, has nice features, and has good range. You're not sacrificing lifestyle when going from a $16k car to a $20k Prius, but it does cost more. And the Prius is far more successful than the EV1 or original Insight. We should focus on abdundant clean, somewhat sustainable energy. I think we'll improve the environment much quicker by giving people lots of clean energy than to tell them to sacrifice. In addition, lots of other problems, like cleaning water and reducing pollution, become much easier to solve when we have lots of energy.

[2019] The Tesla is an even better example of "don't have to give up anything" car than the Prius.

Labels: environment, future

Setting the Carbon Tax #

The carbon tax is a tax on CO₂ emissions. It aligns incentives of business (profit) and society (stable climate) by giving businesses an opportunity to make more money if they find ways to reduce their CO₂ emissions.

One open question with the carbon tax is how to choose the tax rate. Several countries already have a carbon tax, but they seem to set it at a fixed rate, or increase it by a fixed amount each year. Even the Carbon Tax Center says, “There is no magic formula or right number”. I think they're approaching it wrong. Carbon taxes are essentially prices on carbon emissions. Governments shouldn't set prices, and they shouldn't set carbon tax rates either. The market should do it, with a little help from the government.

First, we should decide what level of CO₂ emissions are “sustainable”. You can think of this as the “supply” of available emissions. There is no need to go below this level, although doing so will not be harmful. We should be able to continue emitting at the sustainable level for thousands of years. This level is then set as the eventual sustainable target.

Our current emissions are rather high. We can think of this as “demand”. Since demand is higher than supply, we need to raise prices (the carbon tax rate, currently 0% in the U.S.). We need to decide when we want to reach the sustainable level, and then interpolate target levels from the current level to the sustainable target. This might be a straight line for simplicity, but could also be an S-curve or exponential decay.

For example, let's say that the current CO₂ emissions are 6 billion metric tons, and we decide that 1 billion metric tons, combined with more forests, is sustainable. Let's further suppose that we want to reach this target in 10 years. That means we need to reduce emissions by 0.5 billion metric tons each year, so we set our target for 2009 to 5.5, 2010 to 5.0, 2011 to 4.5, etc., until 2018, at 1.0 billion metric tons.

Each year (or perhaps every month), we look at the current level of emissions and the target level, and increase or decrease the carbon tax rate. If we're emitting more than the target, we'll increase the tax rate. If we're emitting less (which may happen in a few years, if all the businesses are competing to increase profits by reducing emissions), then we decrease the tax rate. By altering the tax rate in this way, we can stay close to the target.

The problem on the business side is that if the tax rates change every month, there's a lot of uncertainty (just as for any prices that change suddenly every month), and it's hard to change plans that quickly. What will likely develop is an insurance market. Insurers will sell insurance that the tax rate won't go up much, and businesses will buy the insurance to hedge against sudden increases. Does this eliminate the incentives for businesses? No! They're now paying insurance and taxes. The cost of insurance is set by the likelihood at the tax rates will go up. The insurance industry is in the best position to guess this, because they'll be visiting the businesses to determine how quickly emission reductions are going into place. The insurance companies will then be able to predict the future emissions, and set insurance rates based on that. Since they're the ones making payouts when businesses (collectively) don't reduce emissions, the insurance companies will then have an incentive to push businesses to act sooner. They also have the incentive to share techniques across businesses. They make more money when businesses collectively reduce emissions.

Most carbon tax proposals use a fixed price and hope that the output will decline. Most cap-and-trade proposals use a hard limit on emissions, and a variable, potentially volatile price. The variable carbon tax rate proposal combines aspects of both approaches. It uses variable prices, but they're varying less often; it uses a target instead of a hard cap, which allows businesses to buy more time; and it generates revenue for society. With a market based scheme, incentive are aligned. Society will want reduced emissions, businesses will want to reduce tax rates (by reducing emissions), and insurance companies will want to reduce payouts (by convincing businesses to reduce emissions). If businesses fail to reduce emissions, they pay an ever increasing compensation to society for the delay. Furthermore, the open question of what to set the tax to, which is open to lobbying, is replaced by the question of how much to change the tax, which I think is harder to game. This scheme also tells you when we've achieved our goal: emissions are at the sustainable target level. Even at this level, we continue the carbon tax to prevent emissions from going up, and we continue to take in revenue from those businesses that produce emissions. This will keep our emissions near the sustainable level.

Labels: economics, environment, future

New EPA mileage ratings: what do you get? #

For my car, after experimenting with different driving styles to see what works best, I'm now getting 26–27 mpg city and 31–32 mpg highway at 75mph and 32–33 mpg at 65mph. The EPA rating for my car is 25 city / 31 highway. However the EPA is now lowering all of their estimates to match the average driver, and with the new estimates, my car is listed as 22 city, 29 highway^*. This might make people feel better about their own driving habits instead of making them think about improving them.

High gas prices are what leads many people to look at gas mileage, but gas prices are not that important. Everyone looks at gas prices because they're printed in big bold numbers at every gas station. Fewer people look at the gas mileage. Learn techniques for using less gas while driving. When the light turns red, take your foot off the gas. Watch for light timing (many lights are timed so that if you drive at the speed limit, you'll get more greens.) For city driving, don't accelerate quickly, and don't drive so fast. Your driving habits make more of a difference than which gas station you go to. And even fewer people look at how much they drive. Plan ahead. Reduce the number of trips you take, and combine multiple errands together into one trip. Move closer to your workplace (this is one reason renters are better off than home buyers—a topic for another blog post). If you're looking to save money on gas, how much you drive is probably the place you should be looking first. Keep track of miles (or gallons) per week.

It's nice to see the EPA adjusting the ratings, but the lower estimates don't match what I've measured with my own driving. The old estimates match closer.

^* This is just an estimate that doesn't take into account wind resistance. My car's coefficient of drag is 0.31, and as a result my real-world highway gas mileage is higher than the estimates. It might be better to take into account drag area as well.

Labels: environment