Let's assume you're the President of the United States, and you ask your head science advisor what we could do about global warming. Here's what the conversation might be like:
Pres: My dear science advisor, what should we do about global warming?
Advisor: First, you should know, sir, that, contrary to popular belief, predicting how much the Earth will warm in say 100 years is very difficult.
Pres: But isn't it true that human's emissions of greenhouse gasses is causing the Earth to warm?
Advisor: It certainly seems to be. There are many agencies who are collecting temperature data from all over the world. Fortunately, the data for the last 50 years or so seems to be pretty well agreed upon.
Pres: And what does the data say?
Advisor: Here's a graph from the United Nation's IPCC report:
Sir, it's hard to tell what's going on with global temperatures unless you look carefully at this graph. Let's look at the top part of the graph for the last 50 years, from 1962 to 2012, where the curve is the steepest. (And as far as we can tell, since 2012 the curve has risen at the same rate). In 1962, the temperature anomaly was about -0.3C. Fifty years later, in 2012, the temperature anomaly was almost 0.6C.
So in the last 50 years, the Earth's global temperature has increased by about 0.9C.
Pres: That's all? What do the other agencies show?
Advisor: NASA and Berkeley Earth show very similar data.
It's important to note what this graph shows temperatures are projected to be. Doubling 0.9C gives 1.8C. So if the temperature continues to rise at this rate, the Earth's temperature by the end of the century, in 2100, will be about 1.8C warmer than in was at the start of this century, in 2000.
Pres: So you're telling me that current projections based upon actual data show a warming of less than 2C by 2100? I've heard predictions of up to 10C by 2100. Where did that come from?
Advisor: Well, sir, there are hundreds of climate models that attempt to predict future temperatures. It's good that we are trying to model climate, but there are literally thousands, if not millions of variables that affect climate. We don't know if we'll ever be able to predict climate, but it's good to try. The various climate models make predictions that vary greatly. So it's best to project from actual data instead of relying on climate models, none of which have been verified.
Pres: What do you think is the most likely temperature increase by 2100?
Advisor: As I said, a 2C increase is the best projection. And there's good data that CO2 emitted by humanity is the main cause of global warming.
You might not know this, sir, but the United States and other developed countries have leveled off, and even lowered their CO2 emissions.
But China and India are building a bunch of coal plants, and they, along with other developing nations will be responsible for the vast majority of increased CO2 emissions. I'm not blaming them. Their economies are growing rapidly and they need lots of energy. Unfortunately, coal plants are their cheapest source of energy.
So to directly answer your question, the amount of global warming that occurs by 2100 is going to be largely determined by how much CO2 China and India produce.
If they start building more natural gas plants and nuclear power plants, that would help.
The bottom line is that if they don't stop building so many coal plants, temperatures might increase by 3C by 2100, or possibly 4C. Understand that these are guesses based on the best evidence we have.
Pres: How bad would such increases be for the world?
Advisor: An increase of 2 to 4C by 2100 would likely be disruptive for some developing countries. It rather depends on how much technology improves over the decades to come, as well as how much more prosperous these countries become. Prosperity allows a country to afford pollution controls, conservation measures, air conditioning, and investment in clean energy.
Actually, there's some evidence that a 2 to 3C increase will eventually be better for humanity. After all, sir, who's to say that the current temperature of the Earth is the best one?
Pres: So the bottom line is that there's nothing that the United States or other developed countries can do to prevent global warming?
Advisor: Not by passing laws that penalize us for our emissions, such as a carbon tax. This will have a negligible effect on global CO2 emissions, but will raise our energy prices, which will hurt the poor the most.
Nevertheless, there is a great deal we can do to help.
Pres: And what would that be?
Advisor: Invest heavily in reseaching 4th generation nuclear power plants. We should be able to get these plants to be inexpensive enough for developing countries to use. These new plants can't melt down, they give off no pollution, and give off no greenhouse gasses.
Even Bill Gates' Foundation is working with other countries to develop next generation nuclear power plants. He'd like to work more with the United States, but there is too much bureaucracy and too much resistance from the general public about using nuclear power. This, even though in over 60 years of commercial nuclear power, not one American has been killed or injured by the radiation from a commercial plant, or even from our nuclear powered aircraft carriers and submarines.
If we can build a 1 Gigawatt plant for $3 billion dollars in 3 years, that would do it. And that's quite feasible.
And with the growth in solar and wind power, within 50 years all countries could be getting their energy from clean sources of power.
Pres: Great! Call Bill Gates right now. The United States is going to be at the forefront of this endeavor. What are you waiting for? Get Gates on the phone!
Tim Farage is Senior Lecturer at The University of Texas at Dallas. He speaks about topics as varied as mathematics, computer science, cosmology, nuclear power, Intelligent Design, and Christianity. The opinions given in this post are his. He can be contacted at email@example.com