Course Summary


Course Summary

Video: Earth 104 Course Wrap Up (3:02)

Click here for a video transcript of "Earth 104 Course Wrap Up".

DR. RICHARD ALLEY: It's a cold day in Pennsylvania and a cold winter in a warming world. Some days this winter, most of Alaska has been hotter than Pennsylvania. Some days, the North Pole was hotter.

And my colleagues working in Antarctica had warmer temperatures than we had here. The global warming is only about a degree so far, and that's small enough that we do have record lows. But it's enough to validate our scientific understanding, which shows, with high confidence, that if we keep burning fossil fuels and releasing the CO2, we face much larger climate changes than what has happened so far.

A little warming, winners and losers. A lot of warming, more and more losers. It gets harder and harder for us. The snow, we knew it was coming because we had a good weather forecast. We know when the hurricanes or typhoons or tornadoes, when floods and heat waves and cold snaps are coming because weather forecasts are good. They're not perfect, but they give us information we can use.

Weather is one roll of the dice. Climate is the average of a bunch of roles, but otherwise, they're often done by the same companies, the same government agencies, people in the same departments and universities, people trained in the same ways using similar or the same tools, and climate projections are skillful, too. They don't tell you what to do, but they do tell you what you can do. And we have very high confidence that, if we use the climate projections together with what we care about and where we want to go, that we can make a brighter future. If we release the CO2 from all our fossil fuels to the air-- burn before we learn-- we face a terrible energy crisis in a world that's much harder to live in. If we used the scholarship, the knowledge of sustainable alternatives, we face a world that can affordably power everyone almost forever.

Since our ancestors first started burning trees faster than they grew back, we have not been able to make a sustainable energy system and now we can. Speaking for the instructional team, we hope you've learned a lot from this course. We hope you've enjoyed what you've learned and that it's useful to you, and we hope that you see the remarkably bright future that awaits all of us. Thanks for coming. 

Source:Dr. Richard Alley

Twelve modules later, we come to the end of the course. We hope that you are energized by our journey together.

Energy is hugely important to us. Quite literally, without external energy sources, most of us would be dead.

We have a long history of relying on an energy source, using it much more rapidly than nature supplies more, suffering as the resource becomes scarce, and then figuring out a new source.

We now rely on fossil fuels for roughly 85% of our use, mainly oil, natural gas, and coal, and some people are working hard to expand fracking to retrieve more oil and gas, and to expand to tar sands, oil shales, and clathrate resources. If we succeed, the total amount of fossil fuel that we can burn is much larger than the amount already burned, but fossil fuel still is likely to become scarce, perhaps late in this century, or perhaps another century or so in the future.

Physics, known for more than a century and really refined by the US Air Force after WWII, gives us very high confidence that the CO2 from fossil-fuel burning is having a warming influence on Earth’s climate. The warmer air picks up and carries along more water vapor from the vast ocean, and melts reflective snow and ice, both amplifying the warming. The ongoing warming we observe, and the history of Earth’s climate and CO2, confirm the physics.

If we burn much of the remaining resource of fossil fuels, we have high confidence that we will cause much larger climate changes than those that humans have caused thus far. Small changes bring winners and losers, but as the changes move well outside experience, losers are projected to grow to greatly outnumber winners. And the uncertainties are mostly on the “bad” side—we don’t see how turning up CO2 can bring paradise, because building something good takes getting many things right, but we can see how too much warming could kill the crops that feed us or even kill unprotected people in the tropics, or in other ways cause huge problems.

Fortunately, we have vast renewable resources available with wind and sun, especially able to supply far more energy than people use, almost forever. The extra costs of such a system are estimated as being a small fraction of what we spend on energy now, perhaps 10%, or 1% of the world economy, with the possibility that additional discoveries will make the renewable sources even cheaper.

Economic analyses show that starting now to reduce fossil-fuel use is economically beneficial. The optimal path involves small actions now that increase slowly but steadily into the future.

Many policy options exist to achieve this. Economists are especially interested in taxing things we don’t like, such as climate-changing greenhouse gases, instead of things we do like, such as our paychecks. Such a “tax swap” may grow the economy a little faster than “business as usual”, even if the benefits of avoiding climate change are ignored.

Actions to reduce climate change, if taken in an economically efficient way, are also expected to improve national security, maintain or increase employment, clean the environment, save endangered species, reduce external damages of our energy system, reduce economic costs of energy-price fluctuations, and allow behavior more consistent with the golden rule.

A shift from fossil fuels to renewable energy sources will undoubtedly shift money around the economy, benefit some people more than others, hurt some people more than others, and otherwise cause many stresses and disruptions. Some of the people who fear that they will “lose” during the changes are vocal in opposing change and are likely to continue to be. This discussion probably will continue through our whole lives and through future generations.

Even if we start to shift away from fossil fuels now, the world is likely to need petroleum engineers and seismologists for a long time in the future. The economically efficient path is slow in part to reduce the damage of firing workers or throwing away valuable investments.

We can see the way to a sustainable energy system, powering everyone on the planet almost forever. And that is a powerful vision of a bright future. We hope you have enjoyed exploring the scholarship of energy and environment, and that it helps you in your future.