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Future Climate of Earth: What does the Science Say? Are We Headed for Near Term Human Extinction (NTHE)? Richard Nolthenius, PhD – Astronomy – Cabrillo College
NTEH people like to quote the work of Sam Carana (not a scientist. Arctic News blog), who created this polynomial fit to 20th century temperature data. It is meaningless for the future 21st Century. NTHE people believe these vast extrapolations Above and Beyond the data are a result of good data analysis. Absolutely False! • --Polynomials are unphysical, are prone to wild excursions, and only possibly reasonable WITHIN the bounds of the data, which this extrapolation is not. • If this is the centerpiece of the NTHM thesis, it is not credible!
OK, But is it PHYSICALLY Reasonable to Expect We are Triggering the “Methane Clathrate Gun”, which will cause Abrupt Climate Change? No. • Clathrates form and can exist only at high pressure and low temperature. Any clathrates existing today are at these conditions. • At 1 C temperature (ocean bottom temps), stable at pressures corresponding to ~330m ocean depth • This is much deeper than the ~50m depths of the Siberian Arctic Ocean, or the ~90m depth where rapid (seasonal) heat transfer can happen through turbulent mixing. • Therefore, expect heating of clathrates will occur only slowly. • Arctic Ocean methane releases have NOT been monitored for long, and are still very small. Most likely explanation is they have been ongoing for a long time.
More important, heating can only penetrate much more slowly down through ocean floor and sediments, down to the level Arctic methane clathrates can exist.We see NO Paleo EVIDENCE of clathrate destabilization – Arctic or elsewhere - during the periods in the past 200,000 years when the Arctic was warmer than today.
What About The PETM (55ma)? And End Permian Extinction (250ma)? • PETM Clathrate destabilization is quite possible here. • But it would take ~ 2,000 years for the heating to reach and destabilize the clathrates at their stability depth, although rapid sea level drop or an extraterrestrial impact could speed this up greatly. • PETM has many hypothetical causes, but there are significant problems with ALL current explanations, including the “clathrate bomb” hypothesis. • End Permian Extinction is more dramatic, killing ~95% of all life on Earth. Associated with massive volcanism in Siberia – lots of possible mechanisms could work. Clathrates could be involved, but we just don’t know enough yet. • Continents very different 250ma, but Siberia at similar (high and so cold-ish) latitude then as today.
Methane Oxidizes to CO2 and Water Vapor with a Half-Life of Only ~9 years • So for the Methane Apocalypse to play out, you need massive amounts of methane release in a time scale of muchless than a century. • This looks very unlikely – not just my opinion, but the judgment of nearly all climate scientists, and articulated well by Dr. David Archer of U. Chicago – a geochemist specializing in climate, in RealClimate.org • Methane currently is 1/250th the concentration of CO2. • So, the Claim: “There is NO QUESTION we have triggered the Methane Clathrate Gun” is then seen as a vast extrapolation unsupported by the evidence.
Do We See Rising Methane in the Atmosphere? Yes. But Methane Relative to CO2 has been Decelerating…
…Until ~2007, Then a Rise Resumption. But Past 7 Years Consistent with Average 30 yr Rise Rate
NTHE Believers Believe it’s Arctic Methane about to Rocket Higher • But it is more likely due to an accelerating population of ruminants (cows, sheep, etc.) • Added to by an estimated $1.5B in leaks due to Fracking and the natural gas boom that started about this time (see “Years of Living Dangerously” for example). • And also, methane from Arctic tundra, and occasional local spikes (“dragon breath”) in methane from Arctic sites, due not to clathrates, but trapped sediment methane from decaying vegetation entombed long ago.
In 2007, Just After End of This Graph, Methane Levels Began Rising Again. But Look Here at Cattle Populations…
Methane Bubbles in Arctic Lakes: This source could increase rapidly, as close to surface. But total amount is tiny fraction of that in the Clathrates. It’ll hurt, but not KILL US ALL
Much Talk about Positive Feedbacks • Guy McPherson terms “Self-reinforcing amplifying feedbacks” • But feedbacks must be modelled correctly to get reasonable answers • e.g. As Arctic Ocean ice goes below 50%, the coefficient in the feedback term will drop, eventually soon to near zero as there’s no more ocean ice to melt • Greenland darkening will only go so far, since fresh snow will continue to fall every winter. • One can’t simply assume every positive feedback takes you to exponential Final Doom. • While we’re at it: I call on the IPCC Scientists to put into those ~35 Global Climate Models in use around the scientific world, every climate feedback we know. A good-faith best estimation, so we are NOT looking just as “what we know for sure”, but what is the most-likely given all we know. • Some big ones already in: water vapor saturation point, etc.
Until Humans Discovered Oil – CO2 Levels Had Been Actually Dropping for ~120 Million Years
NoticeCO2 has been MUCH higher than anything forecast this century, for nearly all of the past 100 million years, with no “Venus Syndrome” • The Venus Syndrome worries center around the following… • Much has been made of a recent paper showing a plot showing the Habitable Zone for solar systems, including ours…
It Looks Pretty Scary! (From Kopperapuet al. 2013). But, Let’s Look Closer…
…if you Read the Paper… • It’s meant to define a very conservative Habitable Zone around other Main Sequence stars and alien planets. • For this purpose, they use a simple 1-dimensional climate model and assume a CLOUD-FREE world. • The authors explicitly state that adding clouds will extend the habitable zone significantly in BOTH directions. Earth has clouds. Lots of them. • For us, near the inner edge, clouds act mainly to reflect more sunlight and cool the planet. It’s a significant effect which moves the inner HZ edge towards the sun, in a safe direction away from Earth. • The implication that we’re teetering on the edge of a runaway Greenhouse Venus Syndrome is just wrong. Climate models all show we are very unlikely to go that route regardless of our CO2 emissions, for many millions of years.
Other Problems with NTHE Claims • Implication: that since humans have never lived in a +3.5C temperature world, we’ll all die – but last time the Earth was that hot, we had not yet evolved as a species – so this is not fair play. • Claim: 440 nuclear reactors around the world will all go into melt-down with societal collapse. But they CAN be safe-mode’d, if we just try. Even if not, implication we’ll all die of radiation is gross extrapolation. • Only aragonite (not calcite) species will dissolve in Ocean Acidification. Other species will take over for dying corals, other perhaps less beautiful species, alas. But the oceans will not ENTIRELY DIE. Very bad, but not total Death. • Claim: Sea level rise of 10mm year is a tripling of the past trend. Sounds VERY scary! But now look at the data on next slide… • Many more ... No time here for them all. Hydro-geologist Scott Johnson has a good discussion of the many exaggerated claims and misrepresentations from Guy McPherson’s past talks. Geochemist and climate expert Professor David Archer at U. Chicago has more, at RealClimate.org (a website maintained by climate scientists to communicating to the public on the latest papers and climate claims.
2007/8 ENSO cycle made Big Slosh Back/Forth of Rain onto Continents and then Draining back to Ocean. Overall Trend Remains the Same…
On Arctic Methane Plume Releases… • Kort et al. 2012 find methane release over open waters of the Arctic Ocean of 2 mg/day/square meter. If you extrapolate (dangerous!) to the entire Arctic Ocean, that corresponds to 10 million tons/yr of methane. This is almost certainly a significant overestimate because they say this rate is only seen over open ocean leads, i.e. it is concentrated because this is where the methane can escape the ocean into the atmosphere. • If we therefore cut this by approximately the open ocean coverage fraction over the Arctic, say 30%, you get about 3 million tons/yr. Compare to 35 billion tons/yr of CO2 from humans, or a factor of 10,000 higher. • Now, this methane release is, and so let’s average over a century to be roughly representative. At that time scale, methane has about 20x stronger heating effect than CO2, pound for pound. (It doesn’t qualitatively change the conclusion below if instead you use 100x, appropriate for a 10 year average) • We get a final number for the heating effect of recent methane release rates from the Arctic, of roughly 20/10,000 that of CO2 emissions, or 1/500th of CO2 emissions. Or 1/100th of CO2 emissions averaged over a decade
So, as David Archer at RealClimate.org points out, we need to keep our eye on the real target – CO2 emissions. At least, for now. • Arctic Ocean methane releases need to rise by a factor of ~100 to become a player comparable to CO2 in additional greenhouse warming. • On the recent 3 Siberian “methane craters” which occurred this past summer of 2014: A calculation of the methane needed to produce these, by David Archer on RealClimate.org, finds it would take 20 million such craters to produce a “Shakhova Event” (50 gigatons of methane released all in a few years).
Some Biologists Are Also Emotionally Committed to Seeing the Destruction of Society • …As pay-back for Homo Sapien’s wanton destruction of innocent species. We are INDEED in Earth’s 6th Great Mass Extinction. Half or more of all species predicted to be gone by late this century. • I sympathize with the feeling! Yes I do. But the reality is – • It is the innocents who will suffer the most in such a scenario…
These People Suffer? Less. So Exactly Where is the Emotionally Satisfying Justice in That?
Without Near-Term Abrupt Climate Change – Are our Prospects Bright? • No. Still Grim…. • National Academy of Sciences Fellow Professor Sandra Faber (and co-author with me on several cosmology papers) gave a recent talk on Earth’s long term future, at UCSC. • Long term (astronomically long) stable human population: Very roughly 50 million, which is less than 1% of today’s 7 BILLION! • 21st Century will likely be ugly… but • When asked whether Climate Change would cause near term Human Extinction – Faber answered “Not even close!”
Arctic Sea Ice Area (Volume even worse) in Collapse. And Now, so is West Antarctic Ice Sheet
…Resulting in Rising Sea Levels (~15 meters eventually, or more) and No Stable Coastlines for Thousands of Years (So How do We Build Ports??)
Population Living Beyond the Earth’s Increasingly Crippled Capacity, Especially in 21st Century
How Have We Gotten Away with it? • Eating our “seed corn”, basically. • 90% of all large fish are already gone • And virtually all arable land on Earth is already turned to crops. Rainforests mostly cut down for fast-food burgers (cattle ranches) • We’ve dug deep into our ancient aquifers. Already 250,000 farmers in India have committed suicide because they cannot afford to dig deeper wells as aquifers drop (suicide, as a message to all, by drinking pesticides they also can no longer afford). This fact has not gotten the wide attention it deserves. • And financially…..
~ All Countries Printing Money At a Furious Rate, and Then Borrowing Against THAT. So Our Numericals Make us “Feel” Richer, but We Aren’t
But, Just as I was About To Write About Declining Crop Yields… • This came hot off the presses – some Irish teenage girls (new winners of the Google Science Fair) appear to have made a huge breakthrough: • Irish teenagers Ciara Judge, Émer Hickey and Sophie Healy-Thow, all 16, have won the Google Science Fair 2014. Their project, Combating the Global Food Crisis, aims to provide a solution to low crop yields by pairing a nitrogen-fixing bacteria that naturally occurs in the soil with cereal crops it does not normally associate with, such as barley and oats. • The results were incredible: the girls found their test crops germinated in half the time and had a drymass yield up to 74 percent greater than usual. • OK - Back to grim forecasts….
Longer Term… • Human Civilization has been cradled and coddled by a 10,000 year period of stable climate, stable unchanging coastlines, and just the right amount of ice on the continents • We’re rudely dumping ourselves out of that cradle, and into the frying pan. • And soon, the Milankovitch cycle insolation isn’t going to help us stay cooler like it has thus far, not again for tens of thousands of years.
During the Past 8,000 years (i.e. Human Civilization), Our Warming Impacts Has Been Offset by Declining Sunlight at the Arctic Circle Summer Solstice, which Controls the Ice Ages… But Soon – No Longer. We’re On Our Own For Keeping Earth Cool, for ~40,000 years
Temperatures Rising Out of the Last Ice Age – And Today’s Spike
Our Choices Today: Disasterous if We Work Hard, Catastrophic if We Do Not • Our “To Do” List… • * Grow up! Realize human well-being, not GDP, is the Gold Standard of virtue. Zero-Growth should be our ultimate goal, and NEGATIVE growth for some time beginning now. • * Design political empowering systems around Human Well-Being as the touch-stone. ALL systems in existence have failed miserably at this. • * Only drastic near-term actions can hope to save us from probable societal breakdown later. • --- ~0.2 child per family, worldwide • --- Tax-and-Dividend: Motivates EVERYone to adopt low-carbon lifestyle • --- No reasonable tech fixes will allow us to “Have cake/Eat too” • But tech fixes still essential:
Tech: What’s Needed… • Massive deployment of solar PV to replace carbon. Nuclear perhaps – hard to get unemotional data and info from either side in THAT debate. • Massive conservation efforts • Pull CO2 from atmosphere (Klaus Lackner’s artificial trees? Rau process and calcium bicarbonate? $200/ton I’ve read, but seems optimistic). Nuclear powered artificial trees? • Reducing atmospheric CO2 to 350 ppm would require producing a cube of CaCO3 the height of Mt. Everest, or similar pile of calcium bicarbonate. • Cost? High!! But What’s a Planet Worth? • Can we DO IT?? It’ll be harder than you think….
Princeton Study (2014) of over 1100 Legislative Bills Finds… • The correlation between the average voter’s desires and the actual bills passed is “Miniscule. Statistically insignificant”. Powerfully financed lobbies run our government. • Concludes: We are not a Democracy. We’re an Oligarchy (i.e. run by the tiny minority of powerful elites. In our case, corporations via their lobbies) • We Need a Wholesale Change of the make up of our Representatives in Government
China 2012: Skynet (yes, they call it exactly that) went Online. Massive supercomputers, “hooked into everything”, connected to 20 million spy cameras, and soon to have facial recognition software to facilitate ID of “dissidents”. Will the U.S. allow a “Skynet Gap” or are we ahead of them in this?
Is This Our Future??? (Probably not, but I’m not 100.00% sure. John Conner – Please Call us!
Even a Complete Collapse of the Industrial World and zero CO2 emissions – and Temperatures will Still Not Go Back Down
My Best Guess of the Future • Rapidly rising food and especially water costs • Resource wars • Have-not countries suffer large loss of life • Possible societal breakdown, but more likely in 2nd and 3rd World tropical countries than here. It’s already begun. • Nolthenius’ First Law: People Learn the Hard Way. • IF (a BIG IF) we do not suffer societal breakdown in U.S. and Europe and Japan, then there’s always hope we’ll wake up and devote a Manhattan Project level commitment to renewables, and to CO2 removal from the atmosphere, willing to pay ANYthing to make it happen – this perhaps by 2050? 2040? • What will the Corporate Overlords do? That’s a big unknown. If they lose control of elections in the 1st World, because of massive grassroots revolt, perhaps there’s hope.
It May Take a Revolution By GrassRoots People in the Powerful Countries to Reclaim the Future • Sidestep the warring Republicans vs.Democrats , who remind me of the war between Oceania and Eurasia in the classic George Orwell novel “1984”. A pointless war which is only a distraction from meaningful action. • My Proposal: Educate – so the People understand the climate crisis is real, extremely dangerous, and that if we don’t solve it, nothing else really matters, and urge a Write-In (this is already legal and unlikely to be repealed) for congressional elections. • Identify in each congressional district someone who will devote 100% to getting a stiff ($300/ton or more) Carbon Tax-And-Dividend law enacted, preferably NOT a major party candidate. And stiff trade sanctions against any other country not joining us. Tax-And-Dividend is the sole goal of Citizen’s Climate Lobby, which I recommend to you. It is the single best motivator of subsequence action to limit carbon.