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planet. And, somehow, we have to make changes that will bring that down to zero. It's been constantly going up.
It's only various economic changes that have even flattened it at all, so we have to go from rapidly rising to
falling, and falling all the way to zero.
This equation has four factors, a little bit of multiplication: So, you've got a thing on the left, CO2, that
you want to get to zero, and that's going to be based on the number of people, the services each person's using on
average, the energy on average for each service, and the CO2 being put out per unit of energy. So, let's look at
each one of these and see how we can get this down to zero. Probably, one of these numbers is going to have to
get pretty near to zero. Now that's back from high school algebra, but let's take a look.
First, we've got population. The world today has 6.8 billion people. That's headed up to about nine
billion. Now, if we do a really great job on new vaccines, health care, reproductive health services, we could
lower that by, perhaps, 10 or 15 percent, but there we see an increase of about 1.3.
The second factor is the services we use. This encompasses everything: the food we eat, clothing, TV,
heating. These are very good things: getting rid of poverty means providing these services to almost everyone on
the planet. And it's a great thing for this number to go up. In the rich world, perhaps the top one billion, we
probably could cut back and use less, but every year, this number, on average, is going to go up, and so, over all,
that will more than double the services delivered per person. Here we have a very basic service: Do you have
lighting in your house to be able to read your homework? And, in fact, these kids don't, so they're going out and
reading their school work under the street lamps.
Now, efficiency, E, the energy for each service, here finally we have some good news. We have
something that's not going up. Through various inventions and new ways of doing lighting, through different
types of cars, different ways of building buildings -- there are a lot of services where you can bring the energy
for that service down quite substantially. Some individual services even bring it down by 90 percent. There are
other services like how we make fertilizer, or how we do air transport, where the rooms for improvement are far,
far less. And so, overall here, if we're optimistic, we may get a reduction of a factor of three to even, perhaps, a
factor of six. But for these first three factors now, we've gone from 26 billion to, at best, maybe 13 billion tons,
and that just won't cut it.
So let's look at this fourth factor -- this is going to be a key one -- and this is the amount of CO2 put out
per each unit of energy. And so the question is: Can you actually get that to zero? If you burn coal, no. If you
burn natural gas, no. Almost every way we make electricity today, except for the emerging renewables and
nuclear, puts out CO2. And so, what we're going to have to do at a global scale, is create a new system. And so,
we need energy miracles.
Now, when I use the term "miracle," I don't mean something that's impossible. The microprocessor is a miracle.
The personal computer is a miracle. The Internet and its services are a miracle. So, the people here have
participated in the creation of many miracles. Usually, we don't have a deadline, where you have to get the
miracle by a certain date. Usually, you just kind of stand by, and some come along, some don't. This is a case
where we actually have to drive at full speed and get a miracle in a pretty tight timeline.
Now, I thought, "How could I really capture this? Is there some kind of natural illustration, some
demonstration that would grab people's imagination here?" I thought back to a year ago when I brought
mosquitos, and somehow people enjoyed that. (Laughter) It really got them involved in the idea of, you know,
there are people who live with mosquitos. So, with energy, all I could come up with is this. I decided that
releasing fireflies would be my contribution to the environment here this year. So here we have some natural
fireflies. I'm told they don't bite; in fact, they might not even leave that jar. (Laughter)
Now, there's all sorts of gimmicky solutions like that one, but they don't really add up to much. We need
solutions -- either one or several -- that have unbelievable scale and unbelievable reliability, and, although there's
many directions people are seeking, I really only see five that can achieve the big numbers. I've left out tide,
geothermal, fusion, biofuels. Those may make some contribution, and if they can do better than I expect, so
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