“We think that this is the most extreme version and it’s not based on facts … It’s not data driven. We’d like to see something that is more data driven. It’s based on modeling, which is extremely hard to do when you’re talking about the climate.”
–White House press secretary, Sarah Huckabee Sanders, speaking at a White House press briefing Tuesday about the Trump Administration’s assessment of the Trump Administration’s recently released climate report
Wow! If that’s true, it’s no wonder President Trump doesn’t “believe it!”
Well, gee, let’s just have a look at that over the next few days, shall we? After all, the report is publicly available:
Claim:Global climate is changing rapidly compared to the pace of natural variations in climate that have occurred throughout Earth’s history. Global average temperature has increased by about 1.8°F from 1901 to 2016, and observational evidence does not support any credible natural explanations for this amount of warming; instead, the evidence consistently points to human activities, especially emissions of greenhouse or heat-trapping gases, as the dominant cause. –Volume II, Chapter 2: Our Changing Climate, Key Message 1
Data: Oh, look, here’s some! It’s right at the beginning of Chapter 2!
The black line in the graphs is made up of the average values of the global temperature measurements from thermometers scattered around the globe. Numbers from measurements are what we refer to in science jargon as “data.” (I’ve discussed the origins and measurement methods of that data in detail here.) Looks like the temperature has been going up since 1880, when we started really systematically burning fossil fuels.
In the top graph (a), the yellow line is a model of what scientists calculate the temperature would have been accounting only for natural processes that might change it. Volcano eruptions, tiny changes in solar energy output and Earth’s orbit. Lots of data — measured aerosol particle counts from volcanic eruptions that have occurred, and so on — go into the calculation of the yellow line, which is done with a model (that model, itself, is informed by laboratory measurements of radiation scattering by aerosol particles, etc.) There’s a pretty big difference between the black line and the yellow line in recent years — looks like natural causes can’t explain our temperature data.
The middle graph (b) considers the modeled temperature effects of all the human activities that might influence global temperature. Again, lots of data (more below) goes into these calculations. The red line is the modeled expected temperature based on all the anthropogenic (human-induced) effects and neglecting all natural causes. Not perfect, but it fits the black measurement data from our thermometers much better then the yellow line in (a).
The bottom graph (c) considers all the natural and human-induced effects to make the orange calculated line. The orange line pretty much sits right on top of the black measurements.
Sarah:“modeling … is extremely hard to do when you’re talking about the climate.”
Well, she’s right. The model isn’t perfect, and that’s why there’s an orangey cloud around the orange line in (c). The cloud represents a scientific assessment of the uncertainty in the model.
The graph above is a summary of tons of data, much of which is laid out in some detail in Volume I of the administration’s climate report, released in 2017. For example:
the global temperature has been going up since the Industrial Revolution and not really before that; and
it’s explainable mainly by emissions of greenhouse gases, and not at all explainable without accounting for greenhouse gases …
with perhaps a teeny, weeny little bit of help from a natural increase in solar irradiance.
In fact, the claim at the top appears to be nothing if not “data driven!”
Sarah seems to doubt the veracity of the model — the orange line and uncertainty cloud in graph (c) — for making forecasts about the future. I mean, it’s not perfect. Maybe Sarah doesn’t like the way the black line squiggles down while the orange line squiggles up around the year 1910. Point taken.
But, assuming the quality of life of my children and grandchildren, and the future survival of human civilization on Earth, might well depend on decisions we make right now, the question is, is the orange model good enough to make those decisions?
Sarah “would like to see something that is more data driven.” Well, we could wait and go on with business as usual, as Sarah seems to suggest, until we just make more temperature measurements clear out to the year 2100 and beyond. Then, we would have all the data. Our conclusions about fossil fuel combustion and the climate would be precisely and perfectly “data driven!” No models required! Great idea!
“I don’t believe it.”
–President Donald Trump, when asked on the White House lawn yesterday for his thoughts on the new climate report prepared by over 300 climate scientists and policy experts spread across 13 departments and agencies of his own administration and citing thousands of peer-reviewed scientific findings
“You’re going to have to have China and Japan and all of Asia and all these other countries, you know, it addresses our country … But if we’re clean, but every other place on Earth is dirty, that’s not so good.”
–President Donald Trump, further expanding on his thoughts to say (I think) that if he did believe the report produced by his own government (which he doesn’t), he would point his finger at other countries, for example China, Japan, and a bunch of other countries in Asia he can’t remember the names of (which, unlike the United States, have not announced their intention to withdraw from the Paris Agreement, an agreement that seeks to bind all nations in a cooperative effort to mitigate climate change)
“…the continued warming that is projected to occur without substantial and sustained reductions in global greenhouse gas emissions is expected to cause substantial net damage to the U.S. economy throughout this century, especially in the absence of increased adaptation efforts.”
–New climate report, Summary Findings, 2. Economy
“While mitigation and adaptation efforts have expanded substantially in the last four years, they do not yet approach the scale considered necessary to avoid substantial damages to the economy, environment, and human health over the coming decades … Future risks from climate change depend primarily on decisions made today.”
–New climate report, Summary Findings, 4. Actions to Reduce Risks
“Ecosystems and the benefits they provide to society are being altered by climate change, and these impacts are projected to continue. Without substantial and sustained reductions in global greenhouse gas emissions, transformative impacts on some ecosystems will occur; some coral reef and sea ice ecosystems are already experiencing such transformational changes … without substantial and sustained reductions in global greenhouse gas emissions, extinctions and transformative impacts on some ecosystems cannot be avoided in the long term.”
–New climate report, Summary Findings, 8. Ecosystems and Ecosystem Services
“Rising temperatures, extreme heat, drought, wildfire on rangelands, and heavy downpours are expected to increasingly disrupt agricultural productivity in the United States. Expected increases in challenges to livestock health, declines in crop yields and quality, and changes in extreme events in the United States and abroad threaten rural livelihoods, sustainable food security, and price stability.”
–New climate report, Summary Findings, 9. Agriculture
“Lasting damage to coastal property and infrastructure driven by sea level rise and storm surge is expected to lead to financial losses for individuals, businesses, and communities…”
–New climate report, Summary Findings, 11. Oceans & Coasts
“Impacts from climate change on extreme weather and climate-related events, air quality, and the transmission of disease through insects and pests, food, and water increasingly threaten the health and well-being of the American people…”
–New climate report, Summary Findings, 6. Health
“In the absence of more significant global mitigation efforts, climate change is projected to impose substantial damages on the U.S. economy, human health, and the environment … It is very likely that some physical and ecological impacts will be irreversible for thousands of years, while others will be permanent.”
–New climate report, Report-In-Brief, Key Message 2: The Risks of Inaction
The President’s refusal to “believe” this report, the consensus conclusions of the best experts in his own government;
his determination to continue pursuing policies that worsen the problem and, in the pursuit of ephemeral profits primarily for a tiny minority of fossil fuel executives and shareholders, put us on a course to permanently and irreversibly harm the world’s ability to support our children and future generations
The Act established the USGCRP, a program with 13 contributing federal agencies and departments, and provided that the program shall produce a comprehensive national assessment report to policymakers every 4 years. The new report is the second part of the fourth resulting National Climate Assessment, focusing on impacts, risks, mitigation and adaptation options for the nation. The first part, focusing on the underlying physical science of climate change, was published last year.
Following are the federal agencies and departments that contributed to the report:
U.S. Department of Agriculture (USDA)
U.S. Department of Commerce (DOC), including the National Oceanic and Atmospheric Administration (NOAA), which administratively coordinated the report
U.S. Department of Defense (DOD)
U.S. Department of Energy (DOE)
U.S. Department of Health and Human Services (HHS)
U.S. Department of the Interior (DOI)
U.S. State Department (DOS)
U.S. Department of Transportation (DOT)
U.S. Environmental Protection Agency (EPA)
National Aeronautics and Space Administration (NASA)
National Science Foundation (NSF)
Smithsonian Institution
U.S. Agency for International Development (USAID)
Why was the report released on Black Friday?
Weird story here. The report was initially scheduled to be released between Dec. 10th and 14th during a large scientific conference in Washington, D.C. Instead, officials announced early last week that the report would be released on the afternoon of Black Friday. In a press conference, NOAA officials declined to provide an explanation, saying only, “It’s out earlier than expected … This report has not been altered or revised in any way to reflect political considerations.”
Hence, rescuethatfrog.com, which views climate change as a huge priority, has devised the clever strategy of resurrecting the news story on Monday. Cyber Monday even, when perhaps many eyes will be online? Hope it works.
Please help it work by sharing this information with your friends and family!
If there’s one most important takeaway from this report, it’s this. The main conclusions and forecasts are essentially the same as the previous 2014 National Climate Assessment, but with the significant addition that climate change effects are readily observable and affecting American lives now. The wildfires in California and flooding events on American coasts are directly attributed to climate change. Far from being a boon to the U.S. economy, the report does not mince words in tracing a direct line from continued fossil fuel use to substantial and intensifying future harms to the U.S. economy, in diverse sectors from farms to fishing to real estate to health care to tourism, starting right now.
“It shows us that climate change is not a distant issue. It’s not about plants, or animals, or a future generation. It’s about us, living now … It’s not that we care about a 1-degree increase in global temperature in the abstract … We care about water, we care about food, we care about the economy—and every single one of those things is being affected by climate change today.”
Even if a person were to distrust the UN Intergovernmental Panel on Climate Change (IPCC) findings on climate change, it would seem this report would carry some weight. After all, it represents the consensus findings of hundreds of experts within our own government — people literally tasked with putting “America First.” So, what’s weird is the transparent incongruity between the conclusions of a broad swath of the U.S. government, as represented in this report, and the attitudes of the President, who frequently advocates for “America First,” and many of our other elected representatives.
Case in point:
Brutal and Extended Cold Blast could shatter ALL RECORDS – Whatever happened to Global Warming?
-President Donald Trump, ignorantly confusing weather and climate on Twitter just last Wednesday. Deep thought: Is the president really that ignorant? — hard to believe since he has the opportunity of being advised by hundreds of experts in his own government on the outrageous idiocy of this tweet. Or, does he know better but calculate that he can nevertheless score political points with this tweet because WE are that ignorant?
Counter-point:
“If the United States were to try and achieve the targets in the Paris Agreement, then things will be bad, but we can manage … But if we don’t meet them, then we’re talking about hundreds of thousands of lives every year that are at risk because of climate change. And hundreds of billions of dollars.”
CNN — Planet has only until 2030 to stem catastrophic climate change, experts warn
New York Post (later republished by Fox News) — Terrifying climate change warning: 12 years until we’re doomed
Popular Science — What you should know about the new climate change report
Motherboard — We’re ‘nowhere near on track’ to meeting our climate change goals, UN report says
The Economist — Why the IPCC’s report on global warming matters
I’ve spent some time reading the report, which is publicly available here, and this post is to share some of the key takeaways using 4 of the key IPCC graphs.
Though the articles above are largely factually correct, I disagree with the tone of some of them. In particular, I hate the title, “Terrifying climate change warning: 12 years until we’re doomed.” Believing we’re “doomed” is just as paralyzing and irresponsible as denying climate change. It has the effect of externalizing the problem, making it seem like an act of nature or something that’s being done to us. In fact, we are only “doomed” to the extent that we allow ourselves to be.
And, let’s be very clear: insofar as “doomed” means “dispossessed of homes, livelihoods, liberty, and cultural identity by the effects of climate change,” people (including Americans) are already being doomed this very moment. Just read my posts on Shishmaref, Kiribati, Fiji, or indeed Miami. Or, watch the news about the latest hurricane landfall and imagine a future in which those hurricanes intensify decade upon decade. Or take a trip to the Western U.S. during the summer. Or, read about the African “Road of Fire” populated by migrant people fleeing drought, water shortage, crop failures, and resulting violence in their former homes.
The point of the IPCC reports is to rationally describe the challenge and to forecast risks as a result of various policies we might pursue, over which we have control, with the ultimate purpose of defining policies to limit the damage and reduce the future risks.
Who wrote it. There is evidently some question about this among some folks.
“It was given to me. It was given to me, and I want to look at who drew, you know, which group drew it. Because I can give you reports that are fabulous, and I can give you reports that aren’t so good.”
It’s actually not a “drawing” per se, but it does contain many informative graphical renderings, two of which we will look at in this post.
In less than 10 minutes of dedicated Googling, I was able to ascertain with a great deal of clarity “who drew” the IPCC Special Report. The report was written by 91 scientists and government agents. Of those lead authors, the greatest number (7) were Americans; the other 84 were from 43 other countries. The lead authors synthesized contributions from 133 contributing authors who drew scientific data and conclusions from over 6,000 cited references in the scientific literature, primarily peer reviewed scientific studies. Drafts of the report were reviewed by some 2,000 registered expert reviewers from 124 countries who generated 42,001 expert review comments that were considered during production of the final report.
To be absolutely clear, there is no “opposing scientific view” on climate change with anything even minutely approaching the credibility of the above detailed effort. The IPCC reports represent, quite literally, the best human understanding of climate change, its predicted consequences, and possibilities for its mitigation.
Why they wrote it. At the time the Paris Agreement was adopted in December, 2015, the 195 nations signing the agreement committed to “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels.” The latter goal was advocated for by the Pacific island nations, which stand to lose the most (which is to say, everything) from even mild levels of global warming compared with our current state. In response to that advocacy, the IPCC was invited to publish, in 2018, a special report on the distinction in global risks between 1.5°C and 2°C of warming, as well as global emission pathways required to achieve one outcome vs. the other. Basically, to answer the question, “Is going through heroics to achieve 1.5°C of warming worth it compared to 2°C of warming? And, if so, is it possible?” This is that report.
What it says, in a nutshell. The report is detailed. It’s 5 chapters and hundreds of pages long. Its key conclusions are very succinctly summarized in a 3-page list of Headline Statements and a 33-page Summary for Policymakers. I highly recommend reading them both. If you’re American, read them before you vote on Nov. 6.
But this is also a case where a picture is worth thousands of words, and so I’d like to reproduce here a couple of the figures the scientists “drew.” If you take nothing else away from the Special Report, sit for a moment with these two images.
The top panel is a graph of global average temperature increase (above the pre-industrial average) vs. year. The grey, squiggly line up to 2017 is the historical measurements (the same data I discuss in detail here). It’s squiggly due to natural variations, which create statistical uncertainty represented by the orange band around the historical data. The orange dashed line is the average projected temperature going forward at the current rate of emissions and global warming, and the horizontal orange error bar represents the statistical uncertainty in the time at which warming will reach 1.5°C. So, we can expect to reach 1.5°C of warming around 2040, but anywhere between 2032 and 2050 accounting for uncertainty. (How old will you be? How about your kids? Your grandkids?)
The purple, grey, and bluish plumes to the right of the top panel are projected global temperature rises based on 3 emission scenarios illustrated in the bottom 3 panels of the figure. The leftmost panel (b) shows annual net CO2 emissions (amount of CO2 emitted by fossil fuel use minus amount of CO2 removed by tree growth, etc.), while the center panel (c) shows net cumulative CO2 emissions. The rightmost panel (c) shows cumulative “non-CO2 radiative forcing,” a fancy set of words for emissions of greenhouse gases other than CO2, such as methane. Starting with the “middle” grey plume of future temperatures, that’s what is expected if we follow the grey emission trajectories in the bottom panels: reduce our global net CO2 emissions to zero by 2055, in addition to a healthy reduction in other greenhouse gas emissions. If we accomplish the first part, but don’t reduce other greenhouse gas emissions, we get the purple projection. If we are more aggressive, reducing CO2 emissions to net zero by 2040, as well as accomplishing a healthy reduction in other greenhouse gases, we can achieve the bluish projection.
Thus, it remains possible to ensure we limit warming to 2°C, and it’s even still possible to limit warming to 1.5°C, but either scenario will require dramatic changes in our energy economy over the next 20-35 years.
These are bars that show scientists’ best consensus forecasts of the severity of impacts and extent of risks in each of a number of categories as a result of allowing the planet to warm various levels above pre-industrial temperatures. The grey band indicates our current level of warming. The risks and impacts get worse as the planet gets warmer (white = “no problem,” purple = “big and irreversible problems”). Anticipating skepticism and in acknowledgement that forecasts are uncertain, the risk colors in the various categories are labeled to indicate their levels of certainty based on available data (M = “medium,” H = “high,” VH = “very high”).
“Even the scientists were surprised to see … how much they could really differentiate and how great are the benefits of limiting global warming at 1.5 compared to 2 [degrees Celsius].”
You can easily see in these simple bars the reasoning behind a goal of limiting warming to at most 2°C, or better yet 1.5°C — that’s the range over which key risks and impacts of interest to us (“heat-related morbidity and mortality,” anyone?) are going from “detectable” to “severe and widespread.” Risks in many of these categories are specifically spelled out in simple language in the 3-page Headline Statements, a quick and informative read.
In looking at the graphs above, it’s important to remember the specificity of the question being answered in this latest Special Report. Don’t interpret the “worst” purple plume in the top graph to be “the worst case scenario.” Any of the projections in the above graphs are actually quite good scenarios, which will result from an impressive feat of social and technological success — transforming our economy to reach zero net carbon emissions by mid-century. When we have done that, we will have good reason to be proud!
For a “worst case,” you need to look at similar graphs published in the last full report of the IPCC, the IPCC Fifth Assessment Report (2014):
The above pair of graphs show, on top, annual carbon emissions historically (black) and into the future (various scenarios). The grey scenario is “business as usual,” in which we refuse to admit the problem and just keep on as we have been. The blue scenario is one similar to those considered in the new Special Report: reduction to zero net carbon emissions around mid-century. The bottom graph shows how much warming we expect for each of the given scenarios, which is just a simple result of how much total CO2 we’ve put into the atmosphere. “Business as usual” — climate change is a “Chinese hoax” and all that — is expected to get us around 4-5°C of warming.
Now, in the graph below, are the same risk bars applied to the broader range of temperature rise we might experience based on our choices starting right now. Lots of reds and purples associated with 4-5°C!
“This report gives policymakers and practitioners the information they need to make decisions that tackle climate change while considering local context and people’s needs. The next few years are probably the most important in our history.”
“You have scientists on both sides of it. My uncle was a great professor at MIT for many years, Dr. John Trump. And I didn’t talk to him about this particular subject, but I have a natural instinct for science, and I will say that you have scientists on both sides of the picture.”
(I can totally identify! My own Dad was a pharmacist for many years, and later the CEO of a hospital. I find I have natural instincts for both prescribing therapeutics and running medical institutions. So amazing, isn’t it, that one can be super good at something apparently fairly complex and specialized, even without any formal training in that thing, just by virtue of having a blood relative who was successful at it? Who wants to consult me about what to take for that rash? I’m pretty sure I can run a hospital in my sleep! Wanna come to my hospital during your next illness? Natural instincts, baby!)
“That is true, there are scientists on both sides. On one side, all the scientists. On the other, one guy who runs a blog called RealTrueAmericanScienceEagle.jesus.”
Lesley Stahl of 60 Minutes: “…what about the scientists who say [climate change is] worse than ever?”
President Donald Trump: “You’d have to show me the scientists because they have a very big political agenda, Leslie.”
Lesley Stahl: “I can’t bring them in.”
President Donald Trump: “Look, scientists also have a political agenda.”
I agree that scientists have a “very big political agenda:” To save the human race from making an enormous, needless mistake.
Beyond that, it’s hard to imagine what Trump could possibly mean by his assertion that “scientists also have a political agenda.”
It’s unclear to which scientists Trump is referring, but the other recent time he wondered aloud about the identity of scientists was in reference to the authors of the recently released IPCC Special Report, in which it was concluded that limiting global warming to 1.5°C above pre-industrial levels will avoid significant risks our civilization will face if we only limit global warming to 2°C, and further that it will take substantial action by the world’s governments, the parties to the Paris Agreement of which have currently committed to voluntary actions that (assuming they are actually taken) may achieve the limitation of warming to around a much higher 3°C:
President Donald Trump: “It was given to me. It was given to me, and I want to look at who drew, you know, which group drew it. Because I can give you reports that are fabulous, and I can give you reports that aren’t so good.”
I am not a member of the President’s substantial White House staff, but it turns out I was able to rapidly identify the scientists Trump wants to know about. I used Google. Plus, I looked at the IPCC Special Report itself, which is publicly available. It took me about 10 minutes to discover a fairly detailed accounting of who the scientists are.
The IPCC Special Report was written by 91 scientists and government agents. Far from shrouding themselves in any sort of secrecy, many of them have been made available by the IPCC for public interviews; I suppose the President of the United States would likely be quite successful in availing himself of such an interview, if he can squeeze it into his existing schedule of other interviews with luminaries such as Kanye West. Of those lead authors, the greatest number (7) were Americans; the other 84 were from 43 other countries. The lead authors synthesized contributions from 133 contributing authors who drew scientific data and conclusions from over 6,000 cited references in the scientific literature, primarily peer reviewed scientific studies. Drafts of the report were reviewed by some 2,000 registered expert reviewers from 124 countries who generated 42,001 expert review comments that were considered during production of the final report.
So that’s the scientists, identified.
It’s hard to understand how such a diverse group of people could possibly have any common “political agenda,” as that phrase is usually understood to mean something like, “an attempt to achieve together a political outcome of mutual benefit,” unless that political agenda is simply reducing risks to the future of humanity based on knowledge. The scientists reside in over 40 nations, represent many tens of the world’s cultures, work for hundreds of separate institutions, and their work is financially supported by a tremendous number of independent sources. At least, the 84 of the lead authors who are not Americans are, by definition, not Democrats. The over 6,000 cited references from which the data were derived were each the result of an independent scientific study, most of them independently reviewed by any of thousands of combinations of other experts as part of the scientific peer review process. How could the scientists in question possibly mutually benefit in any financial or other way by perpetrating some sort of falsified set of conclusions? And how could such falsification possibly be achieved, even assuming the 91 lead authors wanted to do such a thing, given the scientific peer review process?
It’s just an absurd notion, and anyone who believes such a thing is willfully and outrageously ignorant.
Rather, I’ll submit that the scientists in question share precisely two things in common:
A belief in the scientific method; and
A love of children.
If that’s a “political agenda,” then I guess they’re guilty as charged.
As for President Donald Trump, I’ll further propose that he doesn’t like the scientists because:
Check this handy voting guide, prepared by Vote Climate U.S. PAC. The mission of the PAC is “to elect candidates to get off fossil fuels, transition to clean, renewable energy and put a price on carbon, in order to slow global warming and related weather extremes.”
The voting guide gives each candidate a score from 0 to 100 with respect to that goal based on voting records, public statements, etc. You can search for candidates by name or, conveniently, by your zip code.
If you aren’t convinced that mission is important, you could…
Check out the most recent Special Report released by the International Panel on Climate Change (IPCC) this past Monday, which concludes with scientific certainty that we are currently on track to pass 1.5 degrees C of warming, relative to pre-industrial times, by around 2040 and around 3 degrees C of warming by 2100 with dire consequences for much of the word’s population. (I recommend the “Headline Statements” and “Summary for Policymakers,” both brief and informative reads.)
This is the 9th episode in a series recounting the history of measurements, data, and projections related to global climate change. If you’re just joining, you can catch up on the previous episodes:
Episode 1: Beginnings (or two British scientists’ adventures with leaves and CO2 measurements)
Episode 2: First measurement of anthropogenic global warming
Episode 8: Of islanders, aliens, and frogs. A cosmic test for humanity. Part 1.
Episode 9
“But where are they?” exclaimed the physicist, Enrico Fermi. He was sitting at lunch one summer day in 1950 at the Los Alamos National Laboratory with another physicist, Edward Teller, and two nuclear scientists, Emil Konopinski and Herbert York. Each of the scientists had contributed vitally to the creation of the atomic bombs that ended World War II. (Incidentally, 2 of the 4 scientists were American immigrants, 1 was a first-generation American, and 1 was part native American. You might say they perfectly represented the strength of the American melting pot.)
Improbably, Fermi was referring to space aliens.
Intrigued? If not, you’re brain dead! Everyone wonders about alien stuff!
It was the continuation of a conversation about the possibilities and limitations of interstellar travel that had started earlier in the day, and the reasoning was this:
Our galaxy contains billions of stars like our sun, and many of those other suns are billions of years older than ours;
If it’s common for stars like our sun to have Earth-like planets, some of those may have developed intelligent life and civilizations like our own;
Some of those civilizations may have had a “head start” of billions of years on ours;
They may have developed interstellar travel (which didn’t seem like a great stretch, since these 4 very guys — having recently unlocked the secrets of nuclear fission — had been discussing interstellar travel earlier that day and other civilizations might have had billions of years longer to have been thinking about it — consider the strides we’ve made in transportation in just a couple hundred years);
Even at a “slow” pace of a fraction of the speed of light, it would only take a few million years for an interstellar-travelling civilization to cross the entirety of our Milky Way galaxy;
So why hadn’t space aliens already landed on the White House lawn? Why hadn’t we seen evidence of them with telescopes, etc.?
In short, “Where are they?”
The above set of questions would later be called the Fermi paradox. Today, there is a Wikipedia article about it, and it’s the subject of systematic and active study by astronomers, cosmologists, and astrobiologists. At the time Fermi first posed the question in 1950, it was immediately compelling to many scientists. Given a growing realization among them that “Earth-like” (wet, warm) planets were possibly abundant in our galaxy, it suggested that there might be some “Great Filter” that prevented intelligent civilizations like ours from either beginning or lasting long on those planets. Optimistically, the Great Filter was something related to the biological evolution of intelligent life, making us a unique or very rare success story. Pessimistically, intelligent life was fairly common but the Great Filter was some existential challenge that prevents intelligent civilizations from lasting very long. You have to imagine scientists in the 1950’s thinking, “like they all discover nuclear fission and then get in a fight and blow themselves up.” It was a conundrum, and the answer seemed important to the fate of humanity. Looking for evidence of the other civilizations that seemed like they should exist began to seem important.
A few years later in 1959, a pair of physicists, Giuseppe Cocconi and Philip Morrison, published a paper in one of the most selective scientific journals making the case that the best way to look for alien civilizations was to search for radio signals from them. Unlike light, which is blocked by interstellar dust, radio waves penetrate unobstructed through great distances of space. And, they reasoned, a civilization as advanced as or more advanced than ours would likely have learned to manipulate and communicate with radio like we have. Thus was born an international radio astronomy effort that persists to this day as the Search for Extraterrestrial Intelligence (SETI). By 1961, a group of scientists led by the astrophysicist, Frank Drake, and including a young Carl Sagan (whom some readers will remember as the writer and presenter of the 1980’s TV series, Cosmos) had boiled the Fermi paradox down to a short mathematical equation, called the Drake equation, that could be very efficiently written on a postage stamp:
N is what the scientists wanted to know, the number of alien civilizations we can detect radio signals from;
R* is the rate of star formation (number of stars that form each year);
fp is the fraction of those stars with planets;
np is the average number of planets, given a star has them, that are “Earth-like” (where life could potentially form);
fL is the fraction of those planets on which life does form;
fi is the fraction of those planets on which the life evolves intelligence;
fc is the fraction of those intelligent species that develop civilizations involving radio communications; and
L (rather frighteningly) is the average lifetime of those civilizations.
This may seem silly, but it’s not. Boiling a nebulous question like, “Where are the aliens?” into a number of (at least potentially) quantifiable factors had the power of making a big question into a set of smaller questions that different groups of scientists could actually work on.
And they have. NASA’s many robotic missions in the decades since have had many scientific objectives, important of which have literally been to measure key terms in the Drake equation.
Image credit: NASA/JPL-Caltech/Cornell Univ. The steep cliffs of Victoria crater, showing layers of exposed bedrock providing a geological record of billions of years that NASA’s mobile geology lab Opportunity studied in 2006.
Our other planetary neighbor, Venus, has proven harder to explore in detail due to its current harsh surface conditions, but recent NASA models consistent with data from robotic missions and Earth-based observations suggest it could have had a water ocean and habitable temperatures for as much as 2 billion years of its early lifetime before it became a hellish place due to a runaway greenhouse effect.
We’ve also looked much further afield in search of planets beyond our solar system. Since 1995, astronomers have been able to observe stars with sufficient precision to detect the “wobble” caused by planets orbiting them. Since 2009, the Kepler space telescope has hunted planets by staring at a field of stars long enough to see the cyclic dimming as orbiting planets pass in front of them. The nature of each planet and its distance from its sun can be sorted out based on the extent and periodicity of the dimming.
Based on these explorations, we now know the following:
Our own solar system, in its history, has hosted at least 2 and maybe 3 habitable planets.
Planets are not static, and the habitability of a planet can change. Mars was once habitable, and now it isn’t (at least for complex life). Earth wasn’t always habitable for us. Before the Great Oxidation Event about 2 billion years ago, during which now-extinct bacteria began producing oxygen by photosynthesis, we wouldn’t have been able to breathe.
fp in the Drake equation, the fraction of stars with planets, is about 1. Just about every star you see in the night sky hosts at least 1 planet.
npin the Drake equation, the average number of planets in a star’s “habitable zone” where water would be liquid, is about 0.2. That is, about 1 out of every 5 stars hosts a world that has the right temperature for life like our own.
To me, these discoveries are incredible. There are a lot of planets that could potentially host life, and even intelligent civilizations! But what are the chances that any one of them develops life, intelligent life, and a civilization like ours? And, how long does such a civilization typically last? We are still lacking any good information about the last 4 terms in the Drake equation (fL, fi, fc, and L). It would seem we will be lacking that information for some time, since we so far only know of one intelligent civilization (us), and getting to other stars in reasonable time frames remains a substantial technical challenge.
In a 2016 paper, astrophysicist Adam Frank and astrobiologistWoody Sullivan showed that we can still make important conclusions about alien civilizations — conclusions relevant to our own project of civilization — with what we know now. The two scientists re-arranged the Drake equation to ask, not how many alien civilizations exist now, but an easier and still interesting question: How many alien civilizations have ever existed in the history of the observable universe? This question can be expressed in a re-formulated Drake equation:
Now, N* is the total number of stars, which we know. There are about 2×1022 in the observable universe. We know the next two terms from astronomy work (see above), we have no idea about the following three terms, and the pesky L term (average lifetime of intelligent civilizations) is taken away because we are asking how many civilizations have ever existed in the observable universe, not how many exist right now. Frank & Sullivan combined the three remaining terms we don’t know into a single fraction, fbt, which is the fraction of planets that have ever existed within the habitable zones of orbits around stars that go on to develop biology that results in a technological civilization:
Now, we can ask and answer the question, “What is the likelihood that we are alone in the history of the observable universe?” That is, what would fbt, the probability that a habitable planet develops an intelligent civilization, have to be in order for Neverto be just 1? We can calculate the answer based on what we know:
That is, for us to be alone in the history of the universe, the probability of a physically habitable planet developing a technological civilization would have to be less than 2.5×10-22 — less than a 0.000000000000000000025% chance. To put that in context, the chance you will be struck by lightning 3 times during your lifetime is 1×10-12. That’s a probability 4 trillion times larger than fbt would have to be, given the sheer number of habitable planets, for us to be the lone civilization to have developed in the history of the universe. If we are the only one, then nature would have to be incredibly biased against the development of intelligent life.
There are optimists and pessimists. Since we’re talking probabilities, we’re all free to think what we want. As for me,
I don’t generally fret that I might get struck by lightning 3 times; and
The above math makes me think we are almost certainly not the only intelligent civilization to have faced the challenges of filling up its home planet. In fact, there have very likely been thousands. This is an amazing conclusion to ponder.
What wisdom can we glean from that knowledge? What common experiences might we share with, perhaps, thousands of alien civilizations possibly living, or having lived, on worlds our telescopes have already seen? Without crossing over to science fiction, what can we say we know about what an alien civilization might be like?
We know a defining feature of any civilization like ours would be its ability to harness energy from its planet’s star. Prior to civilization, each person had the energy of one person with which to do stuff. Now, if you live in an industrialized country, you probably use the equivalent of about 50 people’s energy every day just to control the temperature in your house. If you jump in your car that gets 25 mi/gal and start driving, you immediately begin using the energy equivalent of about 12 people. A fundamental feature of a civilization like ours is the ability to magnify our power by harnessing and directing a star’s energy. That’s exactly what we’re doing whenever we make a bonfire, drive a car, fly on an airplane, or send a text message. Dolphin’s and chimpanzees are smart. They use tools and communicate through language. But they don’t build fires. Each dolphin or chimpanzee has exactly the energy of one dolphin or chimpanzee at its disposal. They don’t harness additional energy from the sun; hence, they are not civilized.
Since we’ve spent decades studying other planets, we know pretty much for certain what sources of energy would be available for any intelligent aliens seeking to develop a civilization:
Burning stuff (combustion). We started by burning trees, which stored energy from the sun and converted it to biomass over a period of years. Later, we discovered our Earth had given us a great gift: fossilized biomass (oil, gas, coal) from millions of years of its previous experiments with life. Most of the energy that fuels our civilization still comes from burning stuff.
Hydro/Tides. If a planet has water or other liquids flowing on its surface, that motion can be harnessed to generate energy.
Wind. If the planet’s atmosphere generates wind, the wind can be used to harvest energy.
Solar. The planet’s star’s radiation energy can be directly harvested by low-tech (think black plastic), high-tech (think photo-voltaic), or organic (think photosynthesis) methods.
Geothermal. Heat from deep within the planet, generated by storage of it’s star’s radiation or tidal energy, can be tapped by a civilization on the planet’s surface.
Nuclear. If the planet has stores of radioactive elements like uranium, the energy evolved when they decay by nuclear fission can be captured and used. We also believe we may someday create energy by nuclear fusion — by fusing hydrogen molecules to make helium like the stars themselves do. But we haven’t yet proven it.
That’s pretty much the whole list. We know, because we’ve studied astronomically or sent robots to visit lots of planets and stars. Energy in the universe comes from stars, and stars shine on and gravitationally pull on planets, and those are the ways of directing star energy if you live on a planet.
To the extent that it’s successful, any alien civilization’s energy use will eventually affect its home planet. Some methods of energy use will affect the planet more strongly than others. In our case, as we’ve been studying in this series, burning stuff creates carbon dioxide which traps the sun’s radiation energy which heats the atmosphere and then the oceans.
What happens when the aliens’ population gets large, when it begins to fill up its home planet and when its energy use begins to create significant planetary responses?
In a 2018 paper, Adam Frank and three other scientists applied to this question the same type of math that was applied to Easter Island in Episode 8. In that episode, two linked mathematical equations, describing the growth of the human population on the island and the growth and consumption of the resources on which the humans depended, accurately predicted the early growth and eventual catastrophic collapse of the human population, as captured by the archaeological record.
Here, the scientists applied the same type of math to an entire planet (also a sort of island) inhabited by an intelligent, civilization building population. One equation modeled the population growth and its consumption of energy. A second, interdependent equation modeled the response (temperature rise) of the planet to the method of energy generation. There were two means of generating energy. The first (like fossil fuel combustion) caused a strong planetary response. The second (like solar) caused a mild planetary response. At some point (either soon or late after detecting the planetary response), the population could switch its energy generation method from the first method to the second method.
The scientists found four broad categories of solutions to their equations, depending on the rate at which the planet responded to the population’s energy generation and the timing of the population’s switch to the lower impact energy resource. The four different types of outcomes are shown in the plots below, where the solid line is the population and the dashed line is the planetary “temperature.”
Figure from Chapter 5 of Adam Frank’s 2018 book, which I recommend. Four types of histories for an intelligent civilization on a planet with two sources of energy (one with a high impact on the planet and one with a low impact). The civilization starts by using the high-impact source and switches to the low-impact one at some point. The size of the surviving population (if any) depends on the interplay between the speed of the planet’s response to using the first source, as well as the timing of the switch.
Rather frighteningly, the most common outcome was some extent of a “die-off,” as shown in plot A. In these numerous scenarios, growth in high impact energy use drove a significant change in the planetary state that strongly reduced the planet’s capacity to support the population, even after the population switched to the lower impact energy source. This often resulted in significant population reduction before restoration of the planet to an equilibrium (though changed) state; in plot A, the surviving population was only about a third of the peak population. Two out of every 3 people died during the collapse.
Some simulations provided hope. Populations that switched to the more sustainable energy source early enough, relative to the planetary response, were able to achieve a soft approach to a sustained population, as shown in plot B.
Populations unable or unwilling to change to a sustainable resource were doomed to collapse, as shown in plot C. The time before collapse was dictated only by the rate of response of the planet.
Perhaps most scary of all was the type of scenario shown in plot D. In these scenarios, the population switched to the more sustainable resource, but too late. The planetary system and the population appeared to begin to stabilize, before suddenly rushing to collapse as planetary response feedbacks took over. This, I think, is one of the most underappreciated features of climate change. Geology is slow. We can already see at work glimmers of the types of positive feedbacks that, once underway, could drive our planet to a very different state despite our best efforts. Arctic ice melts, reducing the solar reflectivity of the entire Arctic region of the Earth, causing Earth to absorb more solar radiation. Thawing Arctic permafrost releases formerly trapped methane, a greenhouse gas 20 times as potent as carbon dioxide.
We can’t necessarily call off climate change when we decide we’ve had enough. The decision is time sensitive.
A cosmic test.
Why are we talking about aliens?
Here’s the thing. In American politics (which appear to be mirroring the politics of the democratic world), we are currently divided into two tribes. The voice of each tribe, through monetary distortions of the systems that elect our politicians, is dominated by the most extreme elements of the tribe. Each tribe is telling itself a story about climate change.
The story being told by the extreme elements of each tribe is objectively wrong.
The Story of Tribe #1. Humans are greedy. We are carelessly, wantonly destroying the Earth. From the beginning, the burning of fossil fuels was a nasty, unnatural method of fueling the fires of our greedy desires and Earth’s destruction. We are immorally destroying the planet, primarily in the service of the very rich. We should be ashamed for burning fossil fuels.
The Story of Tribe #2. The Earth and its resources are our birthright. We have used those resources, including fossil fuels, to great effect. Unburdened capitalism is beneficial, and has unleashed the full power of the human spirit. Limiting that progress with fake “evidence” of problems is immoral. The costs of addressing your unproven problems are unjustified. Even, “God had guaranteed us an ultimate solution to our problems.”
These are my own interpretations of the two extremes that currently animate us. Please forgive me any inaccuracies, and try to honestly answer whether you identify more strongly with one of them.
I, myself, identify more strongly with one of them (Tribe #1) but, having studied this for a year, I know it’s a mistaken position. We are not a greedy, evil species that’s wantonly consuming a helpless Earth. The Earth is fine. It was fine before there was oxygen in its atmosphere for us to breathe, and it may well be fine when the next life evolves that’s well adapted to the planetary temperature we create. Further, we are not some greedy, evil blight on the Earth because we burn fossil fuels. In fact, the fossil fuels were a gift from Earth’s previous life experiments. They are fundamental to us having built a civilization in which we can have this conversation. On any alien planet, given our understanding of astronomy and physics, the same energy resources would very likely be used first. We are not greedy and evil, we have just been trying to do what humans do — live comfortably, free ourselves from the threats of diseases and predators, raise kids. Earth’s fossil resources were a gift to us, one we have used to build our civilization, but one our scientific evidence tells us we dare not use much longer.
The story told by Tribe #2 is also problematic. The Earth is not our birthright. Our own solar system has featured at least one, and maybe two, other planets that have been habitable at one point but lost their habitability. There are no guarantees. The only protections we have from a bleak future, as a species, are knowledge and acting on that knowledge.
In fact, evidence gathered from significant study of both nearby and faraway worlds makes a strong case that the urgent challenge we currently face with climate change is a cosmic test that would face any intelligent, technological civilization on any planet in the universe. Further, it almost certainly has faced other alien civilizations already, perhaps thousands. It may well be the “Great Filter” proposed as one solution of the Fermi paradox.
This should focus our thinking. Just as much smart work has been required to prevent a potentially civilization-ending nuclear war, smart and coordinated work will be required to find our way through this challenge. We really have no excuse. Thanks to decades of work, we have the technology to switch to low-impact energy sources. The only thing standing in our way is our own ability to agree on a set of facts, compromise on a rational set of solutions, and execute. A basic law of life is “survival of the fittest,” and this is probably a cosmic test of our civilization’s societal fitness.
But what course of action can we all agree on? We need a framework in which we can make steady (and rapid) progress while still arguing about the details. I’ve put quite a bit of thought into that, and I’ve read widely over the last couple years. I believe there is such a framework. It’s a framework we’ve already used with great success (hint: it gave you your smart phone). It’s one that could ensure consistent progress, while allowing all of us the freedoms of choice we value.
That will be the subject of Episode 10. Stay tuned.
All 435 seats in the U.S. House of Representatives
35 of the 100 seats in the U.S. Senate
36 of the 50 state governorships
Numerous other state and local elected officials
Homework:
What are your candidates’ beliefs, proposed policies, and sense of urgency regarding global climate change? Are they consistent with the scientific evidence, what we see with our own eyes, and the need to provide for future generations?
