Q: What can kids between the ages of six and 18 do to help stop global warming and/or save our glaciers?
Also, do you think that, like so many times before, the ice caps and glaciers are just receding and will eventually come back?Lindsborg Middle School, Lindsborg, Kansas
Kids are key to solving this problem; after all, it's you who will inherit the planet and will likely pay the price of climate change. Educate yourselves and others. Insist on getting the facts, and then act on them. Help your parents understand this problem. They trust you. As you learn more, you will see that there are things you can do, like argue in favor of fuel-efficient cars, better insulation and good windows and doors in your home, and buy products from companies that care about the environment.
On your second question, they will likely come back, just as they have in the past, but it will be a long time before that happens. The study of past climate, or paleoclimatology, tells us that when the Earth has high levels of greenhouse gases like we have today, it stays warm for hundreds of thousands to millions of years. The changes we are making today will last a very long time if we don't take action.
Q: Despite your own research and the research of so many other climatologists, have you any opinions as to why so many people still deny that global climate change is a real phenomenon that deserves urgent and immediate attention?James Rochford, Glendora, California
Well, James, I'm not an expert in psychology, but with that caveat, I will venture my opinion, based on years of observation. In many cases, people find it hard to believe that humans could change climate. The Earth just seems too big for us to have that kind of power. This is understandable, given that all generations prior to ours saw the Earth as basically infinite in some way, whether it was land to settle, or the capacity of the air and water to absorb our wastes.
We've reached an important threshold in human history now, when we humans do indeed have the capacity to change the planet. We are changing climate. We make as much nitrogen fertilizer as all of the bacteria on land, the natural source of this key nutrient that makes life possible. We move about 10 times more dirt than natural erosion does. Google the "Earth at night" and check out how Earth looks from space; we light it up, and nearly all of those lights are powered by fossil fuels. I think that fundamental thresholds like the one we have recently crossed take time to sink into people's thinking and actions.
Of course, there are also those who have a monetary stake in the status quo, or who simply don't want to accept the reality of human impact on Earth, and they will not believe. But the Earth doesn't care; it will respond to physics and chemistry, not pundits or public opinion.
Q: Without the presence of the ice on our polar caps, it would seem reasonable to assume temperatures on our planet would rise dramatically, similar to a glass of icewater after the ice had melted. If the polar caps are the cooling agents of our atmosphere and they virtually disappear, what would be left to "cool" our climate? This would concern me more that the rise of sea level. Thank you for contributing to a great TV program. Bob Davey, Laguna Beach, California
While a loss of snow and ice removes one of the main cooling mechanisms of our planet, the Earth will not just get hotter and hotter if ice is lost. Our distance from the sun is far enough so that the Earth would not, for example, get so hot that oceans would boil. The Earth has been nearly or totally ice-free in the past, and life continued just fine. It was much warmer then, with much higher sea level, so times were different, but not uninhabitable.
Q: Is there a way to block the ice from moving out into the ocean? Like a sea wall? Joshua, Grade 3, Edmonton, Alberta, Canada
Well, Joshua, that would be very, very expensive. Imagine building a wall all around Greenland that would hold back ice (it would need to be very thick and strong) as well as hold in the liquid water as the ice melts. That would be far bigger and more expensive than all the buildings in Edmonton put together, and then some.
Q: Up north we are seeing and feeling global warming here: more snow, warm snaps in winter, and spring coming earlier and faster. I know that this has changed fish stocks and other wildlife. What would the rise in sea levels do to marine life and the North Atlantic Drift? Would the freshwater change the flow of warm water along the West Coast? And would it cause a cooling or warming trend to happen? How much time and how much more ice would have to melt to bring this about? Denny, Whitehorse, Yukon Territory, Canada
Rising sea level will create some new opportunities for marine life as land areas flood. Existing habitats, such as coral reefs, may become less habitable. The North Atlantic Drift may slow down as freshwater from Greenland pours into the surrounding ocean. Fresher water is less dense than saltier water, so the sinking of North Atlantic water, which helps move the warm water north, could slow down. This will cool off Europe and Scandinavia, but only temporarily. By the way, our models tell us that you're not likely to feel that cooling in the Yukon. We don't know the answer to your question on timing and amount of fresh water, but it's clearly one of the most important questions we need to answer. We will certainly be watching the North Atlantic carefully.
Q: Is the glacier ice-melt rate the same all over the world? And how does it compare to 100 years ago? Billy Fortier, Lafayette, Louisiana
No, it's not the same all over the world, Billy. Just as the weather is not the same all over, some places are warming more than others, so some glaciers are melting faster than others. A few mountain glaciers are actually growing, but not fast enough to make up for the melting occurring around most of the world. One hundred years ago, many glaciers were growing. The late 1800s was a time of colder temperatures known as the Little Ice Age.
Q: Has the melting of glaciers and ice caps ever happened before? Gwynnie Samson, 6th grade, Lexington, Kentucky
Yes, Gwynnie, it has. When dinosaurs were around tens of millions ago, for example, there were neither Greenlandic nor Antarctic ice sheets. It was much warmer back then, and greenhouse gas levels were much higher in the atmosphere. It is important to recognize that our planet is constantly changing. In the past, the changes were natural, and no one decided to make them happen or not. Of course, we are different in that we can choose to make, or not make, change happen. We recognize the effects of our actions, and understand the concept of responsibility. Even adults don't always take responsibility when they should, Gwynnie!
Q: Would our societal efforts to stem global warming, even at this late date, really have an impact on slowing the ice loss? The domino effects of melt make this seem to be an unstoppable progression. Matthew S. Putzke, Cobden, Illinois
That is a tough question—tough to answer and tough to contemplate. At this time, there is no clear evidence that if we stop burning fossil fuels, and maybe bring down greenhouse gas levels by a number of means available to us, that we cannot stop the melting. Until we know for sure that our efforts are in vain, there's always hope.
Q: My husband is a global warming doubter. He posits that shows such as "Extreme Ice" show only worst-case scenarios and seek to create unnecessary hysteria. My question is, How can one explain to doubters that the threat is real and that we are quickly approaching a tipping point from which the planet may never recover?
He also questions the funding sources for the various research that takes place. Many like him feel that anti-business groups and liberal groups are the only supporters of the science of global warming. What are your primary funding sources?
The program was amazing in its breadth of research and information shared. I eagerly anticipate updates as your progress allows. Thank you for sharing this important information with us all. Lisa Taylor, Florida
Lisa, I tell people that global (as opposed to local) climate is not that complicated, and that if you know how much energy we get from the sun, how much of that energy is reflected by snow, ice, and other reflective surfaces, and how much greenhouse gas is in the atmosphere, you can do a great job of predicting the Earth's temperature changes. You don't need complicated models to do this; it's simple physics. Greenhouse gases are a natural and normal part of our climate system; they raise Earth's temperature by some 60°F, making our planet warm and habitable. The question we face today is whether we are creating too much of a good thing.
I get funding from the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA). Both are Federal agencies. My proposals, like my colleagues', are reviewed by peers, and they frequently turn down my proposals.
You are most welcome, Lisa. Look for James Balog's book, and hopefully updates from him on ice photos as well as future programs on ice research. As they say, a picture is worth a thousand words. While I would like to think that my lectures and writings reach people and change lots of minds, pictures such as you saw in this NOVA/NatGeo special have an impact far beyond mine!
Q: Good show with lots of interesting information. In one segment there was a graph shown of the historical relationship between carbon dioxide, temperature, and sea levels. How much interpretation/extrapolation exists in these figures? Are they hard numbers or open to debate? Thanks. Jon Webber, Salt Lake City, Utah
These are hard numbers, Jon. The carbon dioxide levels are directly measured on air trapped in ice cores. The temperatures come from a number of estimates, and past sea level can be inferred from isotopes (in things like shells) that change as land ice piles up. As scientists, we are professional skeptics, so we always challenge each other. These estimates have stood the test of time.
Q: The middle school where I teach is within a short walking distance of the ocean, Casco Bay specifically. Most of my students' homes are also located nearby. Should we as a community be discussing/addressing this issue now? Julie Pitt, South Portland, Maine
Absolutely, Julie. We are Americans, that's what we do, engage in free and open discussion, and then insist that our voices be heard by those we elect to run the government. We should all discuss this, especially those who face the brunt of the changes.
Q: Everyone learns in school that there was once ice covering most of the continental U.S. Since the last glacial period, this ice has melted or "retreated" away, uncovering the land that 300 million people live on today. Furthermore, glaciers found on peaks in the Rockies and Pacific coastal ranges are merely remnants of this historic continental glacier. My question is: Can't one argue that retreating glaciers today are just a continuation of the same process of melting that began with a climate change about 18,000 years ago? Keith Olson, Fort Collins, Colorado
Good question, Keith. We can track glacier retreat and know that it was essentially done thousands of years ago. Since then, glaciers have grown and shrunk as temperatures have warmed and cooled. We're now warming to a point that mountain glaciers are disappearing, as you can readily see in a trip to the beautiful mountains in Colorado.
Q: I have been an activist on the global warming problem for a few years now, and that has meant that I have worked together a presentation on how to solve it. My conclusion on this problem is that not only is the global warming process accelerating, it is exponentially accelerating. This means that as we look forward we can expect an order-of-magnitude change in melting per unit time versus the seeming prevailing wisdom of scientists of alarm every year as more melting occurs than predicted. When are scientists going to wake up? Is predicting massive melting soon just too scary? Are the scientists in denial? I'll save my solution for later, but it is geo-engineering. James V. Bronke, Everett, Washington
We are awake, James. Our role is to inform the policymakers and public, and we are doing that. When I get a chance to speak out as a private citizen, I do so. Denial is not a luxury that scientists enjoy. We observe, propose ideas, and test those ideas. If it's real, like warming and ice melt, we cannot and will not ignore it.
Q: Isn't the real danger on the other end of the Earth? The West Antarctic Ice Sheet is held up by rocks that are already below sea level. If the sea should rise because of ice melting in the north, couldn't this cause the WAIS to become unstable? John Greenwood, Batesburg, South Carolina
Good point, John. We are watching both poles, and WAIS is a big concern. Google WAIS and see what the National Science Foundation's Office of Polar Programs is doing to understand that ice sheet.
Q: The program mentioned a previous change in climate due to a "change in the Earth's orbit around the sun." I found this startling. How and when did that occur? Might it happen again? Cliff Wilson, Princeton, New Jersey
It happens all the time and is natural. The Earth's orbit around the sun is not circular, it's more oval-shaped, and that oval shape changes with time. Also, the axis on which the Earth spins is tilted so that summer has more light in the summer (all day long above the Arctic Circle), and that tilt changes over time and wobbles around. All of these change either the total amount of sunlight we get or the seasonal distribution of that light, or where on Earth the light shines most. All of these can result in climate changes, as the amount of energy we get from the sun is one of the key parts of climate.