1	20 Climate Questions Answered Quick responses to critics of climate change
2	Climate change science has critics Critics are ok. Need reviews and fact checking. Instinctive denial is not ok. The questions are fair, but much of the rhetoric is getting personal and/or ad hoc. My goal is to answer some of the critics’ more common questions.
3	Simple answers I’m going to give short simple answers. These answers are backed by tens of thousands of studies by thousands of scientists from dozens of countries. Full references available, but two single excellent sources: The Rough Guide to Climate Change by Robert Henson, 2006. IPCC Fourth Assessment Report (Intergovernmental Panel on Climate Change), 2007. http://www.ipcc.ch/
4	Who am I to answer these questions? I’ve studied glaciers and their relationship to climate change since 1989. I’ve published many peer-reviewed scientific papers on this topic. My contributions have been primarily to the underlying math and physics. I am one of thousands who have studied climate change in detail. I am by no means the biggest contributor. But I do have an intimate knowledge of the details, particularly the physics.
5	Climate change work in Alaska and Greenland
6	The basics Humans have released greenhouse gasses into the atmosphere. Mostly in last 100 years. Industrial revolution.
7	The most important gasses
8	Greenhouse gasses trap heat Sunlight comes in (yellow arrow). Light is absorbed by Earth. Earth warms and radiates heat (red arrows). Too much (extra) heat is absorbed by greenhouse gasses and trapped (dark red arrows).
9	How’s it work? Like my dog. Bear soaks in the sun and heats up.
10	Bear reradiates heat Sunlight is converted to heat that is reradiated outwards. Normally, achieves a nice doggy equilibrium of 38°C (101°F).
11	Sometimes surrounds himself with greenhouse gasses Heat trapped by methane and other gasses. Bounces back off of the molecules. Can’t cool off properly.
12	Is this our future? Ok, so the analogy isn’t perfect. But the following pictures of our future are real.
13	Heat causes sea level to rise When glaciers melt, the water goes into the ocean and causes sea level to rise. Heat also causes ocean water to expand (and sea level to rise).
14	Grinnell Glacier, Glacier National Park
15	Climate change summary Current data shows 0.8°C (1.4°F) increase in temperature over last century. relative to 1950-1980 average temp. Rapidly melting glaciers. Rising sea level (20cm in last century). Shifts in plant and animal distributions. Figure from IPCC, 2007, Summary for Policymakers.
16	Climate change future Models project 1.4° to 5.8°C increase by 2100. ~50cm of sea level rise by 2100. and mass human migrations necessary from coasts 37% of all species headed toward extinction by 2050. Loss of fresh water. Panel of US Army generals (2007) have predicted resulting wars over food and water.
17	On to the questions! Ok, that’s the crude basics. Now, on to the questions that I’m frequently asked… I hear them in the checkout line, on the chair lift, etc. You might too. Here’s how you can respond…
18	You can’t even predict the weather! Why should I believe 100 year predictions? I hear this a lot. “Weather models as shown on the nightly TV news are getting more elaborate, but their accuracy is still not very good beyond a few hours or a few days at best. Predictions over decades are futile.” From commentary in the Boulder Daily Camera, January 20, 2008.
19	Why should I believe 100 year predictions? (Part 2) Weather and climate are NOT the same thing. Climate is the average weather over long periods of time. This lecture is in January in Colorado. Can you tell me if it will be warmer here in June? Duh! That’s climate. We can predict warmer weather in June with certainty. Predicting the average weather (climate) is possible (even though the day-to-day variations are harder to predict).
20	Warming schmarming. It snowed sooo much this week, how can global warming be real? AKA: It’s sooo cold this week, global warming must be a hoax. Again, that’s weather not climate. No single storm or cold snap or hurricane can be directly attributed to climate change. We will still have winters. We will still have extreme weather events.
21	Humans couldn’t do all that with puny little cars, could they? (Part 1) Yup. Data shows we have. Cars, planes, industry, etc. We spew ~26 billion metric tons of greenhouse gasses per year. That’s the equivalent weight of 17 billion cars. That’s enough cars to completely cover the surface of the Earth about 3000 times. It would take about 1000 years to count that high. Many different models from many different scientists show that these amounts cause climate change.
22	Humans couldn’t do all that with puny little cars, could they? (Part 2) Where’s 26 billion metric tons go? The Earth isn’t as big as we used to think. It’s surrounded by a VERY thin atmosphere – like a sheet of paper on a basketball. Not much room for all those warming gasses!
23	Humans couldn’t do all that with puny little cars, could they? (Part 3) Consider Mt. Pinatubo, 1991. One volcano spewed ~20 billion metric tons of cooling sulfur dioxide, ashes, etc. One single volcano lowered temperatures by 1.0° C for several years. But we spew more than that in warming gasses every year!
24	Scientists are perpetuating the myth to keep their funding, right? No. That requires belief in a global-scale conspiracy among thousands of climate change scientists AND the governments that fund them. Would only take one credible scientists with credible results to speak up and ruin the conspiracy. Occam’s razor – the conspiracy explanation is too complicated! The core of the global warming research was completed when very little funding was available (1980’s-1990’s). Personal viewpoint: Climate change funding was so hard to find in the 1990’s that I decided to pick up a second skill set as a computer scientist. Sure, institutions self-perpetuate. But scientists are trained to be skeptical. They want to debunk the current theory. Want to change the paradigm. (And make a lasting contribution.) Scientists are not in it for the money.
25	Isn’t it just a natural cycle? (Part 1) No. Natural variability happens. Data shows that human changes are being added on to that natural variability. Very reliable models all show that only mankind’s addition of greenhouse gasses can be responsible. Natural variability alone can’t account for observed warming. All the models agree on this!
26	Isn’t it just a natural cycle? (Part 2) This figure shows temperature data (black line) and climate models with only natural processes (in blue) with both natural and man-made processes (in pink). Clearly, the models only match the data when including the man-made processes. From the IPCC 2007 Summary for Policymakers.
27	But I heard that variations in the sun cause the changes, right? Wrong. Changes in solar output have contributed about 1/3 of the warming over the last 100 years. The rest comes from greenhouse gasses. Very thorough modeling studies done by many different scientists back this up.
28	Isn’t climate science filled with uncertainties? No, not really. The foundations are very solid and based on reliable math, physics, and chemistry. Virtually unanimous agreement among thousands of climate scientists that warming is happening. Most of the “uncertainty” comes from our inability to predict what people and governments will do in the future. So we create scenarios. If governments let CO₂ double, then we expect this… If CO₂ triples, then we expect this… This creates a range of results. Remaining uncertainties are matters of precision. Will it rain more in your backyard or mine? Exactly how much will it warm here versus there.
29	Aren’t the models too complicated to be reliable? (Part 1) No. Complicated does not mean wrong. Your car’s and TV’s are very complicated. But they work just fine. Do you think plasma TV’s don’t work? Much of the physics (thermodynamics) is the same! Not understanding the model is not the same as discrediting it.
30	Aren’t the models too complicated to be reliable? (Part 2) 14 different climate models running 56 different simulations. All simulations shown in yellow. The mean is in red. The actual data is in black. Clearly, the models reliably simulate the data. From IPCC, 2007, The Physical Science Basis.
31	Aren’t the models too complicated to be reliable? (Part 1) “Complexity” is often a relative statement. Want an example? See another of my lectures: Sea Level Rise and Glaciers. I work through some of the math and physics used to help predict sea level rise. To a freshman physics major, this material is complex. To a senior physics major, this material is not so complex.
32	But aren’t some glaciers actually growing? So you must be wrong? AKA: The temperature gauge in the city of ____ shows cooling. So you’re wrong. AKA: I saw An Inconvenient Truth and Al Gore lied about point X. Umm, no. This is called cherry picking. You can’t focus on one piece of contrary data when the tidal wave of evidence supports the opposite conclusion. Besides, we have predicted that some parts of the world will cool, get wetter, snow more, grow bigger glaciers, etc. Those predictions are consistent with a GLOBAL-scale trend of warming.
33	Cherry Picking What if I told you “The average American is 5’7” tall.” Can you trot out Michael Jordan as a contradiction? Duh. No.
34	Isn’t the “hockey-stick” curve based on bad science? (Part 1) AKA: The hockey stick is wrong because ______.
35	Isn’t the “hockey-stick” curve based on bad science? (Part 2) No. This figure has been peer-reviewed by independent scientists many, many times. It’s conclusions are always supported. Scores of scientists contributed to the data in this figure. i.e., it is not a fabrication of Michael Mann or Al Gore. Global warming does not rely on just this one piece of (very strong) evidence. Can you say “cherry picking?”
36	Scientists have been wrong before. Why trust them now? AKA: What about “global cooling” predicted in the 1970’s? That was not a scientific consensus. Only briefly considered by a small minority of scientists. Media latched onto this more than scientists. In part, fueled by concerns about a nuclear winter. Also see next slide.
37	Many scientists disagree, so why should I believe? (Part 1) Umm, which scientists? Where? Global warming is a scientific consensus! It is very hard to find climate scientists that disagree. Out of thousands, you might find 2 or 3. Check their credentials carefully. Have they published and done first hand research in climate change? Or did they just review the literature? Out of thousands, I can find a few people that believe in anything. 998 believe I’m human. 2 believe I’m a mutant alien. I am not discrediting the critics’ intelligence, but it’s a tidal wave of support among the thousands that do this research.
38	Many scientists disagree, so why should I believe? (Part 2) Some of this is the media’s fault. The media wants to present both points of view. The media successfully uses this “debate” model with politics. So media searches out the few critics and gives them equal footing and equal time. This gives the wrong impression that the critics and the climate scientists are equal in numbers. Or somehow equally right.
39	But I read Michael Crichton and he says… AKA: I heard Senator Inhofe [or insert your choice here], and he says… Well, you can choose between thousands of climate scientists, or a science fiction writer… Oh, and now you’ll believe politicians? Check those credentials!
40	Couldn’t something undiscovered be to blame? Yes, but physics says that greenhouse gasses cause warming. Now have the MUCH harder problem of explaining why modern physics is all wrong. Oh, and broken thermodynamics means your car, computer, and plasma TV’s wouldn’t work anymore. Rats. Occam’s razor, again.
41	Who cares? Isn’t a 1° to 2°C temperature increase insignificant? No! Every 1°C rise in temperature requires a 25% increase in snowfall to keep glaciers from melting. So glaciers melt, sea level rises. Ocean water also expands in that heat. Coastal aquifers inundated – no water to drink! Coastal cities inundated. People must migrate inland. Ports must be moved. Huge economic costs. Species go extinct. Agriculture disrupted. Etc.
42	Wouldn’t global warming be a good thing anyway? Define good and bad. That’s a judgment call. But ask the billions that live on the coast. 11 of 15 of the world’s largest cities are at sea level. 53% of the US population lives on the coast. Climate change will be similar to El Niño. Massive flooding, droughts, famines, fires, storm surges, etc. accompany every El Niño. Is that good? Try asking the polar bears. Or coral reefs. Or tropical beaches.
43	Won’t technology come to the rescue? Well, I hope. But you are placing a lot of faith in possible solutions that might or might not exist. Some possible solutions (like spreading ash in the atmosphere) could cause a host of other problems. Isn’t it wiser to mitigate the problem in the first place?
44	Any mitigation will wreck the economy. You don’t want that do you? (Part 1) Wreck the economy? Says who? Get their evidence. Check their credentials! Caveat: I’m not an economist. See! Always check those credentials! But I do know there are two possibilities: Maybe we will wreck the economy. Maybe we won’t wreck the economy.
45	Any mitigation will wreck the economy. You don’t want that do you? (Part 2) Maybe we don’t wreck the economy. Many “green solutions” like recycling have produced major cost savings. Some economists project a green-industry boom. Maybe we do wreck the economy. I’m not sure it matters. Don’t we have a moral obligation? Is a dent in the economy worth saving lives? Saving entire species?
46	Any mitigation will wreck the economy. You don’t want that do you? (Part 3) Either way, reacting to climate problems after the fact could be hugely expensive. Who’s going to pay to move entire cities? Who’s going to pay for resulting wars? Global climate change presents a serious national security threat that could affect Americans at home, impact U.S. military operations, and heighten global tensions. Massive migrations, increased border tensions, greater demands for rescue and evacuation efforts, and conflicts over essential resources, including food and water – such developments could lead to direct U.S. military involvement. From US Military Advisory Board, 11 most-senior retired generals and admirals. Isn’t prevention the wisest choice?
47	Ok, it’s real, but isn’t the response just mass hysteria? (Part 1) That’s a judgment call. At what level is the response over-the-top? To some extent, it is the FOX News syndrome. Death and destruction makes better press. And it’s easy to turn global warming into pictures of dying polar bears. See? But wait, the polar bears are dying! In my opinion the press coverage is warranted! Am I hysterical? Judgment call.
48	Ok, it’s real, but isn’t the response just mass hysteria? (Part 2) Scientists have warned of other big baddies – nuclear winter, pesticide use, etc. And we have become immune to warnings about the “end of the world”. But, this is the first time in history that a group of scientists have so concertedly, uniformly, and relentlessly sought to inform the public about an impending danger. Climate scientists feel a moral obligation. Maybe that should scare us a little bit. The scientists say we have to do something now. Inaction will cost lives and dollars. Our moral obligation to help is not hysteria.
49	But I hate Al Gore. AKA: I really dislike _________. This person is polarizing. Strong words. Too bad. Al’s right. This is not a debate about personalities.
50	Not a debate about personalities
51	In fact, not a debate at all. Questions are productive and instructive! But that’s different from a debate. The scientific consensus is overwhelming. Would you debate that the Earth is round? And actions are most productive of all. Which brings me to the last question…
52	Yeah, well, there’s nothing I can do, so why worry? But you can do something! Small actions by everyone add up to big contributions. Small actions by everyone added up to cause the problem in the first place!
53	Things you can do! Small actions. Doesn’t have to be inordinately painful. Reduce the miles you drive each week. Drive slower (more fuel efficient). Vacation closer to home. Use more energy efficient appliances, light bulbs, etc. Buy wind power (or solar, or…). Recycle. Insulate your home and hot water heater. Use low-flow shower heads. Turn off computers at night. Search the web for more ideas! Did you notice that most of these will save you $$?
54	“Mass hysteria” summary
55	SAVE THIS!
56	And this!
57	And mitigate this.