What is the Greenhouse Effect and what does it have to do with global warming?

Last week we took a look at some basic definitions needed to understand climate change (or global warming). This week we'll discuss the basic principles and history of the greenhouse effect, on the fundamental truths that explains why Earth has the global climate range is has. 

The greenhouse effect is pretty uncontroversial. It is basic physics. And it is why we can live on this planet.

In short, the greenhouse effect is the process by which light energy from the sun, upon passing through the atmosphere and reflecting off the earth, is partially blocked from leaving the atmosphere again. This is what warms the earth.

The basic principle is shown in the picture below.

In a nutshell, short-wave radiation from the sun passes through the Earth's atmosphere. That radiation is absorbed by the surface and reradiates back towards space, but now as longer wavelength Infrared (IR) energy. Some of this longer wavelength energy is absorbed by greenhouse gases (more on those later) and returned to the surface, thus warming the Earth.

For a quick primer about how the greenhouse effect works, check out this animated diagram.

If you want a little bit more detailed information, here is another good source.

And if you really want something to sink your teeth into, try this slightly more technical and expansive site.

One quick caveat. Though it's called the "greenhouse effect," actual greenhouses work slightly differently. The sun energy that comes into a greenhouse and reradiated is physically trapped by the glass. In the atmosphere the trapping is caused by the chemistry and physics of greenhouse gases. So the greenhouse effect is named more for its similar effect and not the actual mechanism. Don't let deniers confuse you on this simple difference.

As noted, this greenhouse effect is not controversial at all. It's well understood and has been demonstrated unequivocally to occur.

In fact, scientific understanding of the basic physics of the greenhouse effect has been building for over 200 years. Contrary to what some seem to think, the greenhouse effect was not invented by Al Gore in 2006 when his movie, An Inconvenient Truth, was released. It was first named in 1827 by Joseph Fourier, who was a mathematician in Napoleon's army.  [BTW, that's Fourier to the left...I included his picture because the poor guy never gets any credit]  In any case, Fourier came up with the idea that outgoing infrared energy would be blocked by gases in the atmosphere, more or less analogous to a pane of glass in a greenhouse. This built on the work of Sir William Herschel, who besides discovering the planet Uranus and writing symphonies had discovered in 1800 that energy can be transported by invisible infrared radiation.

In 1859 a British physicist named John Tyndall identified three main greenhouse gases: carbon dioxide (CO₂), methane (CH₄), and water vapor (H₂O). He discovered that these gases absorb light energy, convert it to heat, and reradiate the heat away as infrared light.

Then in 1896 a Swedish scientist named Svante Arrhenius (that's him, right) calculated that doubling the carbon dioxide concentration in the atmosphere would increase the temperature of the Earth by about 4-6°C on average (roughly 7-11°F). Despite having to make thousands of calculations by hand and the lack of measurement instruments at the time, Arrhenius's estimate is not too far off from the more up-to-date estimates of 1.5-4.5°C (about 3.4-8°F). This increase in global warming due to the doubling of CO₂ has come to be known as "climate sensitivity," that is, how sensitive is climate to the increase in CO₂ and other greenhouse gases. Still another guy, actually a dashing young Englishman named Guy, as in Guy Stewart Callendar, came around in 1938 to estimate this climate sensitivity to be about 2°C (about 3.6°F).

Wow, so it seems that the greenhouse effect is well known and built on knowledge that goes back to the work of scientists over two centuries ago. Knowledge that has expanded as technology has enhanced our ability to measure what we couldn't measure and calculate by computer what Arrhenius and others could do only by hand. It wasn't something Al Gore made up at all. There is, in fact, a whole body of science behind this simple concept.

Of course, we already knew that. Only deniers mention Al Gore in a sort of Pavlovian bell-ringing drool when they don't want to admit the long history of scientific understanding of the greenhouse effect. Actual climate scientists rely on over 100 years of peer-reviewed published scientific research papers (over 200 if you go back to Sir William Herschel's earliest discoveries).

As I noted at the beginning of this article, the greenhouse effect is why this planet supports life. Without it we would be like either Venus or Mars, either too hot or too cold. It is scientific fact that increasing greenhouse gases cause an increase in atmospheric temperature. Without this greenhouse effect, the surface temperature of the Earth would be much, much colder than it is! And that wouldn't be good at all, at least for us humans and most other plants and animals.

For those who are into the mathematical proofs of such things, you can read Proof of the Atmospheric Greenhouse Effect, a paper published in 2008 by physicist Arthur Smith.

So the greenhouse effect is natural and keeps us warm. The problem is that we've created an enhanced greenhouse effect by adding greenhouse gases to the atmosphere at an unprecedented rate, and that is causing the surface temperature to warm. That warming is causing all sorts of other climate problems as well, which we'll go into as this series continues.

That's enough for today. Take some time to become familiar with the general concept of the greenhouse effect. In future posts we'll take a look at the relative contributions of the various greenhouse gases, as well as other "forcings" that affect climate.

[This is part of a series of posts explaining the basic science of climate change. More posts will be added weekly.]

So is it "Global Warming" or "Climate Change?"

One of the things that seems to cause a lot of confusion is the use - and misuse - of the terms "global warming" and "climate change." Frankly, people misuse words all the time and this one example shouldn't be that big of a deal. Mostly the confusion is caused not by the words themselves but by the lack of understanding of the concept of climate change, both from normal ignorance (not everyone can be a climate scientist) and from intentional abuse in order to avoid policy discussions to deal with the science. In either case, it doesn't change the science to say global warming when you should be saying climate change. Still, the jargon used by various professions tends to be confusing to those outside the profession.

So this article begins a series in which basic climate science will be explained for those who want to know but don't have a background in climate science. Feel free to refer to them when talking with your friends, family, or deniers on Facebook and other social networking sites. First up, some definitions so we all know what we're talking about. I'll start with the obvious ones and I'll update as questions arise during subsequent commenting and posting.

"Global Warming" and "Climate Change": As I said, for most people it doesn't matter which you use, but in practice the terms have specific meanings. Remember your high school SAT questions? Well this is more or less like "orange is to fruit" as "global warming is to climate change." An orange is just one of the many kinds of fruit (in technical terms, a "subset"). Global warming is just one component of the many things happening that tell us there is a changing climate (e.g., ocean acidification, melting ice sheets, altered migration patterns). Of course, it's not really that simple, as we will see in subsequent posts, but it's a good start.

"Anthropogenic": Simply put, "man-made." That doesn't mean there aren't natural forces out there also at play; natural forces have impacted climate for millennia. So when scientists say anthropogenic or man-made or human activity they are referring to that component of global warming (or climate change) that is attributable to the things we do - most notably the emission of carbon dioxide (CO2) and other greenhouse gases into the atmosphere. And over 100 years of data tells that what 7 billion humans do make a significant difference to our climate.

"Theory": This is another word that causes great confusion because the general public uses it to mean something completely different than do scientists. To most people, in common usage a "theory" is like "well, yeah, he could win the game in theory." In other words, most people use "theory" when they mean more or less a wild guess, or at best an educated guess. That's not what it means in scientific circles. When a scientist says "theory" he means it is an unequivocal conclusion based on the preponderance (i.e., vast majority) of the evidence. It is built on the forming of hypotheses (proposed explanations for something we observe and measure), the testing and refining of those hypotheses, and then eventually a pretty solid case for what causes what. Hypotheses stay hypotheses as data are collected and analyzed until every attempt to find some other explanation proves futile. Once the evidence is so overwhelming that all other explanations are ruled out it becomes a "theory." In short, things that are unequivocally demonstrated are called theories. Most people wouldn't be too worried about the meaning of "the theory of gravity.;" gravity keeps us from floating off the planet. The same holds true for "the theory of anthropogenic (man-made) climate change." The data are unequivocal; we are warming our climate.

"Scientific Consensus": Another common point of confusion is when scientists say that there is a scientific consensus. In the case of climate change, there is an overwhelming scientific consensus that climate change is happening and it is being caused by human activity. When most people hear this they think of a bunch of people sitting around a table discussing where to go for lunch. "Aha, we've reached a consensus, it's definitely Taco Bell!!" In other words, many people think it's like taking a vote. But that is not what scientific consensus means at all. When a scientist says there is a consensus that means that the issue has been studied for a long time and in many different ways and the sum total of all the collected data from multiple lines of evidence and all of the analysis done by multiple people has eventually built up the evidence to a point where it leads so overwhelmingly to a particular conclusion that the vast majority of scientists agree that what the data tell them is true. That sentence may be a mouthful, but basically it means the conclusion is overwhelmingly, and unequivocally, demonstrated by the evidence. This is the case for man-made climate change.

"Uncertainty": Scientists are always looking at "uncertainty." In every published scientific paper there is a section in which the uncertainties are discussed. In most cases, those uncertainties are quantified statistically to the point of something like "I'm 95% certain the result is this..." This causes confusion to the general public because to most people uncertainty means "we aren't sure." That is not what it means in scientific studies. As science is always collecting and incorporating new data, nothing can ever be said to be 100% "certain." But that doesn't mean we aren't sure. It just means we aren't sure about some particular details. For example, we can be very sure that gravity exists, but there is uncertainty as to exactly how and why it exists. Think about what you would do if the weatherman said there was a 95% chance of rain. That means there is still 5% uncertainty, but I'm betting nearly everyone will have their umbrella handy.

Here are some other terms that have different meanings to the public and scientists (meme from internet, original source uncertain):

 

In addition, the USEPA has compiled a list of useful climate change terms that could come in handy.

Okay, that's all for now. Any other terms that people think need to be defined? If so, put them in the comments and I'll add them to the list.

Weapons of Math Destruction: How Big Data Increases Inequality and Threatens Democracy, by Cathy O'Neil (Book Review)

A hugely important work filled with knowledgeable insights, this book takes a hard look at the promises and pitfalls of big data. Mostly pitfalls. Written by an insider data scientist, the book's title riffs off the infamous Weapons of Mass Destruction (WMDs) of a decade ago, trading the Mass for Math. The clever theme continues with chapters labeled Bomb Parts (basics of mathematical modeling), Shell Shocked (the author's path toward recognizing the problem), Arms Race (going to college)...all the way through Collateral Damage and The Targeted Citizen.

Along the way author O'Neil examines how big data - mathematical models - are now used to determine who gets into college, how corporations target advertising to specific groups, whether you get and keep a job, and assessing credit ratings and insurance risk. Through insider interviews and personal experience, O'Neil documents how model building often integrates the inherent biases of the people building the models, as well as historical biases. In many different ways, and through dozens of pertinent examples, it becomes clear that WMDs are designed primarily to reduce costs and promote higher income for the companies that use them.

Worse, WMDs reinforce societal prejudices and stereotypes, targeting - even if sometimes unintentionally - the poor and minorities, further driving them downward and limiting opportunities for upward movement. The poor are kept poor by reducing access to affordable loans, depressing credit scores, and blocking job options through linkage to factors that are irrelevant or biased. And because these models are black boxes both to the people held back because of them and, often, the people administering and using them, there often is no way to even know why rejections have occurred. Without the model feedback seen in more useful models, these WMDs cause their destruction with no hope of ever improving the algorithms used.

O'Neil jumps from the financial crisis of 2008 to the removal of teachers unfairly to how Google and Facebook influence behaviors simply through their choice of what people see in their feeds - and who gets to see it.

As models, algorithms, automation of processes, and online data collection continue to become more prevalent, and potentially more destructive, this book becomes essential reading. Its valuable insights, whether you agree with everything the author suggests or not, are critical to our informed discussion of what we want our future to look like.

Available on Amazon.

The War on Science: Who's Waging It, Why It Matters, What We Can Do About It, by Shawn Otto (Book Review)

The War on Science is a must read book for scientists and anyone even remotely interested in science or policy or politics or decision-making or life. Yes, that means you.

The book is actually much more than the title suggests. Shawn Otto (one of the founders of ScienceDebate.org) delves deep into the history of science, but also in the psychological, sociological, political, educational, and religious histories and their interactions with science. He points out that the early leaders of this nation were promoters of science. George Washington said "There is nothing which can better deserve our patronage than the promotion of Science and Literature." Jefferson heavily promoted science during his presidency and noted as he was leaving office that "Science is my passion, politics my duty." Great Republicans presidents such as Abraham Lincoln, Teddy Roosevelt, and William McKinley all emphasized the importance of science and technology. The author notes that Republicans were once the party of progressive optimism and tolerance, of environmentalism and finance, of rationalism and national parks. Only recently have Republicans turned against science. [But Democrats have their anti-science as well, which he discusses]

The reasons for this turn toward antiscience are discussed in great detail. Otto digs into the history of religious intolerance for science that contradicts scripture, most notably by the excommunication of Galileo (who, ironically, was devoutly religious), but also with many other examples ranging through history to today. He examines the interplay of antiscience and "freedom," including how fear of annihilation from Cold War/nuclear weapons led to the "live for today" attitude of the 1960s. But not just nihilism, this constant stress and attachment to the "military-industrial complex" caused a suspicion of science.

Further, the book delves into the turn towards postmodernism, which denied the existence of objective truth, claiming that all "truth" is subjectively in the eye of the beholder and that your opinion (often, ignorance) is as good as decades of scientific fact. This postmodernist belief severely damages education, where no longer are students expected to learn from accumulated facts but how they "feel" about reality. The media promotes this subjectivism, combined with the need to create controversy to garner ratings, as well as promote "false balance." All of these erode citizen confidence in science for no reason other than to assuage their fears of the unknown.

Otto also takes a closer look at the "three-front war on science" from identity politics, ideology, and industry. All three provide substantial and substantive background and analysis and should be read closely. The third, "The Industrial War on Science," is extensive and examines the long and fruitful strategies of industries (often working in tandem with religion and media) to deny established science and delay or eliminate any policy action. We saw this for decades as the tobacco industry denied smoking causes cancer, and today as fossil fuel and libertarian lobbyists deny man-made climate change, as well as many other examples. Otto documents in detail the tactics used by denier lobbyists and their hired spokespeople; even quoting from their own strategy materials. He shows also how companies like Exxon and the Koch companies shifted from paying directly to denier front groups to slipping the money in through "dark money" vehicles like Donors Trust and Donors Capital Fund.

The final three chapters look at "winning the war" in the sense of how do scientists and others battle against the misinformation of identity politics, ideologies, and industrial disinformation campaigns. In short, it isn't easy. Otto discusses how to engage in conversations in ways people can relate to. He also proposes a series of 14 "battle plans" to communicate science and overcome denial. The plans begin with something as simple as "doing something;" getting out there and trying to communicate. They continue with specific actions like creating a science advisory organization, pushing for science debates, using science advisors more effectively, and reaching out to religious, educational, and political leaders to help them understand the importance of science and its role in policy making. Otto also suggests that scientists need to fight back against the harassment, disinformation, and personal attacks of denial organizations.

All of this can get rather intense. The book is dense in both information and thought. Otto has done tremendous research in a wide range of science and sociological history to develop the incredible insights he displays in this book. I highly recommend that all scientists read it, but I also highly recommend everyone who has an interest in honest discussion and policy making to read it. Finally, every responsible American citizen should read it as it helps put into context our role as citizens in this democracy. 

Amazon page for War on Science

The Story of Western Science: From the Writings of Aristotle to the Big Bang Theory by Susan Wise Bauer (Book Review)

I highly recommend this book. "The Story of Western Science" is indeed presented as a story, or rather, a series of highly readable stories in 28 succinct chapters ranging, as the subtitle notes, from Aristotle to the Big Bang (and the Butterfly Effect). Bauer's writing style is easy and fresh, even when she is communicating difficult to understand scientific concepts.

The author relies on the writings, i.e., the key historical books and texts, to illustrate each topic, though she brings in numerous other key scientists and writings to coherently fill in the flow of scientific knowledge.

The book is laid out into five Parts, each containing 5-7 chapters:

I. The Beginnings: Here she covers the first attempts to write down the principles of science as they are being developed, the first accounts of the universe, the first thoughts on evolution, the first mathematics to measure the universe, and the transition from an Earth-centered to Sun-centered understanding of our worlds.

For example, After introducing Plato's principles, the differences between him and his student Aristotle, the Archimedean calculations, and the Lucretian principles, she introduces the fundamentally and completely erroneous model of the universe as espoused by Ptolemy. She goes on to Copernicus and his more accurate, though still flawed and theoretical, heliocentric view. Along the way the author deftly points out the development of new ideas and theories, along with their many side tracks and sometimes century-long disappearances only to reappear in different forms and by different researchers.

II. The Birth of the Method: All of the early work by the ancient Greeks and others was largely ad hoc. In this section she traces the influence of Francis Bacon and the development of what would become the scientific method of inquiry. No longer reliant on undocumented grand theory, science would advance by following a system of observation, experimentation, and reasoning. This would be assisted by the improving of instruments and "helps" like telescopes, microscopes, and other devices of measurement and observation.

III. Reading the Earth: This part begins a series of three parts that take focused looks at geology, biology, and cosmology. Ironically, the science of geology got its start in astronomy. As scientists discovered more about the cosmos, they realized that the Earth is not so special, i.e., that it was similar to other planets. Thus, processes that effect other planets and moons, like meteor craters for example, could also happen here. This led to debates about whether changes in the Earth came about slowly by the same processes we see today (e.g., volcanism, erosion) or through catastrophic events (e.g., "the Biblical flood" or asteroid strike); uniformism vs catastrophism. Along the way there are conflicts between religion and science, the age of the Earth, continental drift, and others.

IV. Reading Life: Bauer takes a look at the first systemic attempts to categorize life on Earth. Debates about the origin of species, inheritance of traits and genetics, evolution, and biochemical development were widespread. Again she is able to tease out the key points from their technical basis and present them in ways readers can understand. The shift from the obtuse writing of Copernicus (in Latin) to the writings of Julian Huxley, intentionally designed to be read by a non-scientific audience, are brought to light.

V. Reading the Cosmos: In this final part she examines the broader investigations into relativity, quantum physics, the Big Bang, and Chaos. She shows the limits of Newtonian physics and how Einstein and others replaced it with space-time fluctuations that can be hard to understand even as she makes them more accessible. And then the replacement, of sorts, of that with quantum jumps.

All of this she does adroitly, extracting key principles and documenting the myriad steps and key players as our understanding evolves from one place to the next (sometimes going back steps or skipping steps, only to return to them later). Bauer has done a wonderful job showing how science, and scientists, works.

But Bauer goes one step further. Since she uses key writings of science over the ages as the skeleton on which she hangs her history, at the end of each chapter she tells you how to find the books. She even tells the reader which editions to obtain and which other secondary texts do a good job of explaining the more technical writings. In the front of the book she lists all of the key texts she refers to, separated by Part.

To reiterate, I highly recommend this for anyone who wants to get a solid history of the development of science from the beginnings to today. Bauer does an excellent job of making the science accessible without "dumbing it down."

[The Dake Page periodically reviews books related to science and science communication. To see other reviews click here and scroll down. Click here to reach the Amazon page for the book.]

Science Debates Needed for Presidential Candidates

Science is critical to every facet of our lives, and scientific innovation has been a part of American government since George Washington, John Adams, and Thomas Jefferson. Despite being hamstrung by the Republican Congress, President Obama has been a big supporter of science research to the point of hosting annual White House Science Fairs. But what do the current candidates to take over the job of President say about science?

Science Debate is needed.

We do have a basic idea of where the candidates stand. Democratic nominee Hillary Clinton explicitly said, and I quote, "I believe in science," in her acceptance speech at the convention. She went on to say she believes "climate change is real and that we can save our planet while creating millions of good-paying clean energy jobs."


Republican nominee Donald Trump, in contrast, called climate change a "hoax," and claimed it "was created by and for the Chinese in order to make U.S. manufacturing non-competitive."

Jill Stein, ironically the "Green Party" nominee and a former medical doctor, nonetheless has espoused anti-science positions on vaccinations, homeopathy, and GMOs. Critics have accused her of pandering to the anti-science left wing as much as Trump has pandered to the anti-science right wing.

Libertarian nominee Gary Johnson scores relatively well on basic science literacy in one survey but comes out as anti-vaccination and anti-GMO on another survey. That said, the basic rule of libertarians is to spend as little money and engage in as little government activity as possible, which suggests he would be in favor of cutting science budgets in the executive branch.

Even with these basic overviews, however, we don't know how much priority the candidates would put on science once elected. Issues such as climate change are critical to continue the progress made by President Obama. Other issues such as fracking require more complex assessments and decision making, so here again the ability of the new president to deal with science-based issues is critical. On top of this, of course, are the funding requirements of science agencies like NASA, NOAA, EPA, FDA, NSF, and others. These agencies conduct basic research as well as fund external researchers in addition to their more overt roles.

ScienceDebate.Org is a non-profit organization organized by Shawn Otto, author of the book The War on Science as well as a previous book called Fool Me Twice. Dozens of science organizations have combined efforts to produce 20 Questions related to science to ask the presidential candidate. Questions related to their views on basic science, the anticipated level of priority for their administration, levels of funding, views on education, innovation, public health, water, energy, food, vaccination, and many more. Even immigration has a science component, and one question asks "Would you support any changes in immigration policy regarding scientists and engineers who receive their graduate degree at an American university? Conversely, what is your opinion of recent controversy over employment and the H1-B Visa program?"

Ideally there would be a separate Science Debate in which these questions can be asked directly of the candidates. Barring that, the public should encourage standard debate moderators for the three presidential and one vice presidential debates to ask these questions. Even written responses to the questions would provide the public with input on where the candidates stand on science-based issues. And the public does want that input.

So all of us should be reaching out to the candidates, to debate moderators, and to others in our communities to have these all-important questions addressed by the candidates.

For more info on Science Debate, go to their website.