It’s Earth Day today. This is a day to raise awareness about the environment and issues such as climate change and resource depletion. But I’d like to raise something which is often overlooked though, to do with the economics of climate change. But can we really cut our energy usage by switching to more efficient appliances?

Let’s take energy-saving light bulbs as an example. An standard 100W incandescent light bulb is exceptionally inefficient – it produces about 95% heat, only 5% of that energy is turned into visible and useful light. However, new energy-saving fluorescent light sources can produce the same amount of light for just 20W.

OK, so there are considerations such as the amount of energy which used in manufacturing new fluorescent light bulbs for us to use or the costs of installing additional insulation to reduce heat loss because less heat is now produced by light bulbs. Although they are very valid points, they’re not the issues I wish to explore.

On the face of it, if we all switched from 100W incandescents to 20W fluorescents, there would be a 80% drop in the energy consumption! Hey, presto! But that isn’t the whole story. Because economics tells us that when the price of something falls, consumption increases. In other words, because our lighting systems now consume less energy and cost less to run, people will demand more lighting systems.

Take a look at this graph from the presentation “Energy Services and Energy History: Lighting and Transport in the UK” (slide 11).

The cost of lighting (and efficiency) has been falling steadily since 1300, yet it is obvious that we are using much more lighting now as costs have been falling. Since 1900, the efficiency of lighting improved 50 times. Meanwhile, the amount of lighting used has increased by 155 times. So despite all the huge efficiency improvements over the last 100 years, we’re still using 3x as much as energy as we were before.

What I hope this has demonstrated is that improving energy efficiency won’t necessarily decrease energy usage. But would switching to more energy-efficient bulbs cut energy usage in our developed world today? Perhaps. For me, the cost of leaving the light bulb on is so small that I barely even think about it. So a light bulb which costs less to leave on probably won’t cause me to leave the light on for any longer then I currently do. But in some countries, if the price of leaving the light bulb on is now a fifth, I could envisage households which might decide that rather than just having one light bulb in the lounge on, they could now install a light bulb in every room in the house. This increased usage of lighting would negate any of the benefits of improved energy efficiency.

It might all seem a bit pointless talking about light bulbs, but I chose it as an example because it’s easy to explain and there’s a lot of good data. But this same theory can apply to all kinds of other things.

Let’s say that a new generation of cars has twice the fuel efficiency. This means the cost of running the car is half what it was before. More people will therefore decide to use cars, and perhaps to use cars on those short journeys they wouldn’t have before. Also in the less economically developed countries, this could make running a car a viable proposition for many people.

My conclusion is that we can’t rely on improvements in efficiency to reduce our energy usage. It simply won’t work. In fact, it could even lead to increased energy usage and make things worse. That’s not to say we shouldn’t create efficient light bulbs and cars but they’re not going to save the environment. We need more proactive ways of dealing with our use of fossil fuels.

There’s an article in this week’s New Scientist (12th April 2008, p17) by William Laurance from the Smithsonian Tropical Research Institute entitled “Expect the unexpected” which I thought was really interesting. He talks about some of the unexpected ways in which we’re damaging the planet.

Take biofuels. Many countries, including the USA, have promoted biofuels as alternatives to using fossil fuels. Why? Because when you grow corn, the plant will “breathe in” carbon dioxide. When you put it into your car and burn it, it’ll release an equal amount of CO2. So biofuels are supposed to be carbon neutral and won’t contribute to climate change.

In order to encourage people to use biofuels, governments have subsidised them. In essence, they tell farmers that they’ll give them an additional amount of money for every gallon of biofuel they produce, on top of the amount of money they sell it for. This encourages farmers to produce biofuel because they can earn more money from it: basic economics.

So what’s been the effect of this? Well, US farmers have switched from growing soya to growing corn. This made soya more scarce and drove up the price of soya across the world. The higher soya prices then acts as an incentive to others to produce soya; you can now make more money by selling soya.

That’s lead to deforestation in the Amazon in order to clear the way for soya production. And the deforestation has lead to forest fires.

In the Amazon, the trees help to generate their own rainfall. Why? Rain falls and the dense vegetation quickly recycles the moisture, returning it to the atmosphere so it’ll rain again. As deforestation continues, less water vapour is recycled. That means less rain in the future: a feedback loop.

Anyway, I won’t repeat the entire contents of the article as Laurance gives many other examples of unexpected consequences of rising demand for wooden furniture, logging and fishing.

It does really make you think about how everything in the world can be linked together in so many ways and all impact upon each another. In some of my own physics research, I found that an increase in global temperature would lead to a greater occurrence of lightning. Effects of lightning? Forest fires may be created and nitric oxides are produced. A significant number of forest fires could reduce CO2 absorption. Nitric oxides are fertilisers: could this lead to better forest growth? Nitric oxides also lead to the production of ozone in the atmosphere which is a greenhouse gas. More greenhouse gases = further global warming. Did anybody expect that?

The fact is there are just so many different interlinked processes going on in the world around us. It reminds me slightly of James Lovelock’s Gaia Hypothesis:

The Gaia hypothesis is an ecological hypothesis that proposes that living and nonliving parts of the earth are a complex interacting system that can be thought of as a single organism. Named after the Greek earth goddess, this hypothesis postulates that all living things have a regulatory effect on the Earth’s environment that promotes life overall.

It’s a controversial theory. Says Lovelock on climate change:

He says the global climate treaty, the Kyoto Protocol, is simply an attempt to appease a self-regulating Earth system.

Professor Lovelock thinks the Earth’s attempts to restore its equilibrium may eliminate civilisation and most humans.

He wants a rapid end to the destruction of natural habitats, which he says are key to planetary climate and chemistry.