Today and Beyond - New Evidence and Consequences

There will always be room for improving our climate modeling, For example, as the IPCC AR4 states, there remains significant work to do in understanding the interaction of clouds with aerosols and with their detailed droplet properties. A major reason why cloud modeling has been difficult is the lack of simultaneous measurements of the properties of clouds across all electromagnetic wavelengths over large regions. Earlier satellites had calibration and other problems which limited the ability to do detailed modeling with confidence. Beginning in 2006, however, we have a convoy of satellites which are all looking at the same clouds simultaneously with a wide range of instruments impossible to mount on a single satellite effectively. Dubbed the "A-Train", this satellite convoy has already added greatly to our understanding of cloud/aerosol interactions. See this article in Physics Today. For example, biomass burning produces aerosols exert a net cooling on the environment when the underlying cloud coverage is less than 40%, but net warming when cloud coverage is higher than 40% (Chand et al., Nat. Geos. 2008). Clouds in polluted environments are sulfate-rich and "brighter" (more reflective), and produce less rainfall (Jiang et al., Geophys Res Lett 2008). Now in 2014, the new GPM satellite has been successfully launched - GPM for "Global Precipitation Measurement", which will be able to accurately monitor the changes associated with droughts as global climate change accelerates. Also, Sherwood et al. (2014 in Nature) and now van der Dussen et al. (2015) find that as climate warms, the depth of the convective mixing layer may be increasing, drying the air and reducing low clouds (video here). If so, this is another new amplifying feedback since low clouds help cool climate by reflecting sunlight away from the surface beneath them. Other studies will have to clarify the total land area on Earth subject to this low cloud feedback, which is not part of the Sherwood and van der Dussen cloud physics studies. This new cloud feedback is not included in current climate models of the IPCC AR4 and AR5. However, our improving data on paleo climate when CO2 levels were different is Nature's own modeling simulation. Another feedback associated with clouds is rising heat-driven humidity in the troposphere, already understood, is now making its way into the stratosphere (Dessler et al. 2013) and above, where rising CO2 cause COOLING, and hence a rise in cloud formation and noctilucent clouds (think of them as extreme cirrus clouds), which are happening earlier in the season, and spreading farther south then ever before. (NASA video)

Global warming in the Arctic is reducing the temperature gradient across the polar jet stream, producing wide meanders in the jet stream. This is shown to be associated with extreme weather in historical data (Screen and Simmonds 2014). Current global warming is seeing this as well, and in the future is predicted by climate models to make for more frequent and more widespread extreme global weather events, including California droughts (the current 2012-2015 drought is apparently the worst in 1,200 years). Average temperatures for the American West are up a full +2.0C above pre-industrial levels (vs. +0.85C for the global average in 2014), reinforcing the latest NASA study showing 80% odds of mega-droughts lasting a decade or longer in the American West (Cook et al. 2015). Data from insurance companies (who can't afford to indulge in denialism - they're on the hook for insured losses) shows the accelerating increases in climate-related natural disasters (but tellingly, not non-climate related disasters) over the past 30 years (table at right). The food industry is also facing reality. They are urging policy action or face global food shortages in coming years. A new UN study estimates that the economic costs due to damage to coral reefs alone over just the next 20 years will total $12 trillion, which is comparable to the official U.S. National Debt, and equivalent to $2,000 for every person on Earth. Damages to the animal ecosystems of the ocean are accelerating rapidly (McCauly et al. 2015). We are seeing that the future is virtually certain to be significantly worse than the 2007 IPCC projections. Yet there is clearly no political will to drastically cut carbon emissions. Why? Princeton researchers studied over 1300 legislative bills passed over most of this century and show that the legislation which is passed has zero correlation with what average voters want, but instead is determined by corporate lobbyists - ZERO correlation. It is corporate lobbyists who determine our laws, not average citizens. Average citizens have the vote, but those elected do what the corporations tell them to do, once in office. Click the link - the evidence for this statement is overwhelming.

A consequence of greenhouse global warming which gets little media attention is a cooling stratosphere, as I showed in the denialist claims webpage. The cooling stratosphere is having another effect - cold stratospheric temperatures enhance the destruction of ozone already being caused by man-made chlorine compounds. There is a worsening ozone hole in the northern hemisphere centered on the Arctic. The ozone hole which got all the attention a couple of decades ago was over the Antarctic, which continues to slowly heal. This area, however, has very few people. The Arctic areas are instead dominated by land and peoples; Norway, Canada, Alaska, Russia, Sweden, Finland... It is ozone which absorbs the ultraviolet light from the sun and protects life at the Earth's surface. Life on land was impossible for the first billion years of Earth's history, until an ozone layer in the stratosphere formed. See the results of a recent NASA study on the growing ozone hole over the Arctic. There is another stratospheric effect which is turning out to be more important than earlier realized: growing water vapor from the troposphere diffusing into the stratosphere amplifies climate warming by ~10% at a minimum (Dessler et al. 2013 in PNAS) and so is an additional positive climate feedback, and as with so many others, is not included in the IPCC models.

Falling ice reflectivity due to dust, wildfire ash, and other contaminants to surface ice, are producing a significant new positive feedback heating of 0.31 watts/m² per degree of temperature rise (Pistone et al. 2014), to 0.7 watts/m² per degree of

temperature rise (Flanner et al. 2011), much higher than existing climate models (e.g. the CMIP5 model has 0.10 watts/m² per degree).

In 2011, we saw a new record low in Arctic sea ice volume, lower than the dramatic drop seen in 2007. And in 2012, it is much lower still, as the last of the thick permanent ice melts through. Thin seasonal ice breaks up quickly during the early summer, allowing dark ocean waters to amplify solar heating. The ice is thin enough now that a new positive feedback destroying sea ice is taking effect - the large open areas of ocean permit larger waves to be formed by wind fetch, and these break up thin ice and expose more of it to melting. Like others, this positive feedback is not in IPCC climate models. Another effect of the loss of Arctic sea ice is dropping populations of amphipods and other life at the base of the food chain there. Arctic sea ice extent is being described by scientists as "in free fall". Global warming is beginning to happen more rapidly here in the 21st Century. Tropical climate is expanding poleward, and associated diseases and agricultural pests are doing the same, migrating now at the startling rate of 7 km per year (Nature 2014).

Take special note of three striking facts: (1) The 2007 IPCC AR4 estimated Arctic permanent ice would not vanish till the end of this century, and yet it now looks to be only a few years away at the current rate of loss. (2) The additional heating rate due to the loss of white reflective Arctic Ocean ice is about the same as that due to all man-made CO2 heating. In other words, the forcing on our climate may be as high as twice what we'd expected even just a few years ago. We are already observing sea level rise at a rate of 3.3 mm/year (trailing 18 year average), nearly twice the rate of rise seen in earlier decades. Not only is sea level rising, it is rising at an accelerating rate. In 2014, data from the Crysosat-2 satellite shows that the rate of ice loss in Greenland has doubled in the past 5 years, and tripled in West Antarctica (Helm et al. 2014). The loss rate from these two sources is now 500 cubic kilometers of ice every year. Old IPCC models did not include non-linear effects such as ice cliff failure and hydrofracturing. When these are included, West Antarctica alone contributes as much as 3 meters of sea level rise before the end of THIS century (Pollard, deConte and Alley 2016). Rising sea levels are the next "hockey stick". The costs to coastal cities is estimated to be a thousand billion dollars per year (Hallegatte et al. 2013 in Nature: Climate Change), although domino effects will no doubt add to these direct flooding costs. Flood insurance costs are already skyrocketing, with the Federal government stepping back from what will clearly be a costly commitment. Studies of atmospheric CO2 vs. sea level during the past ~40 million years strongly suggests that we are already past a tipping point above which the Greenland ice sheet will melt completely, as will major parts of Antarctica (over the coming decades and centuries). Part of the mechanism is the strong feedback we're seeing in how regular melting darkens snow (NASA video) , as well as aerosols from rising wildfires (not well quantified), as well as algae colonies in new melt pools, from larger ice grain size, and surfacing of existing particulates buried in melting snow (Tedesco et al. 2016 who conclude existing projections of darkening are "likely underestimated"). Already, the number of moulins shown by satellite data across Greenland has grown from 100 in 2007 to 1,000 by 2012 (41 minutes into this oceanographer's lecture). In a recent paper Foster & Rohling (2013 and full text here) calculated that long-term sea level rise will reach 24 metres (+7/-15 metres at 68% confidence) above present-day sea level once the planet has fully responded to the warming from current levels of CO2. This is likely to be achieved through extensive disintegration of the West Antarctic and Greenland ice sheets, and a substantial part of the coastal sector of the East Antarctic ice sheet" (source). (A reminder to my students - the phrase "fully responded" refers to the fact that we are NOT in thermal equilibrium, that the time scale for ice sheet equilibrium to be established with climate is much longer (5-25 centuries according to Foster and Rohling) than the rapid forcing time scales humans are applying). This means centuries of further warming until these physics time scales are satisfied. Much sooner, however, sea level will rise by 1 meter, likely while today's children are still alive. That will ruin cropland growing fully 1/4 of today's crops, including a significant amount in California (Ward 2013). Well, you say, we'll just grow crops somewhere else... except that over 90% of all arable land on Earth is already converted to human occupation and agriculture. (3) Methane carbon from melting permafrost is not included in the IPCC AR4 projections, even their worst case scenario. Yet a rapidly melting Arctic Ocean will trigger thawing of the Arctic soils as far as 1500 km (900 miles) south of the Arctic Ocean (Lawrence et al. 2008, see presentation here). Arctic soil contains 30% of all carbon in soils worldwide, and twice as much as already in the entire atmosphere. How much of this will find its way into the atmosphere is not clear. Shallow Arctic Ocean methane clathrates could potentially hold much more, and are at some (poorly known but likely low) risk of destabilizing as the Arctic Ocean ice cover disappears and the permafrost "cap" holding it underneath, thaws (early fears by Shakhova et al. 2010 appear now to be greatly lessened ). The mechanism of this hypothesized destabilization is this: loss of Arctic Ocean ice cover exposes the dark ocean to sunlight, raising ocean surface temperatures (well established), and also the loss of ice means significantly more turbulent mixing (well established) of the warm waters to deeper levels, possibly down to the ~130 ft depth of the East Siberian Shelf. We do see consistent methane release to the surface right now; but we don't know if that release rate is rising rapidly with climate change, or has been roughly constant for centuries as post-Ice Age warm water has been slowly melting sea bed permafrost for thousands of years. It's far more likely the latter, after an assessment of the stability of methane hydrates in Siberia. More time and monitoring is needed. Methane-induced drastic climate change is now supported as the cause of the greatest extinction in Earth's history - the end Permian Extinction (Rothman et al. 2014, MIT news summary here), although the specific mechanism is different than today's.

Back in 2010 the National Science Foundation reported on the prospect of methane release causing much more rapid climate change than previously thought. Beyond the permafrost, Arctic lakes contain vast amounts of methane, and as they are now melting, that methane is being released (Walter et al. 2009) in a feedback cycle (i.e. more warming, more methane release, causing stronger greenhouse warming, leading to more thawing and methane release, etc.). This video shows the trapped methane. This methane has been stored in permafrost since the last Ice Age, as shown by radiocarbon dating, and its total quantity available from thawing lakes alone is 10 times the entire methane content currently in the atmosphere. Frozen lake methane is at a much higher risk of escaping to the atmosphere than deep permafrost carbon, or Arctic Ocean clathrates. Add in methane and CO2 from thawing permafrost and global warming accelerates even further. Note that even though methane's current contribution to greenhouse warming is less than that of CO2, methane (pound for pound) absorbs infrared radiation 100 times more strongly than an equivalent mass of CO2 (over a decade time scale). The rapid melting of polar ice seen in 2007 triggered a jump in methane release from melting Arctic lakes. See this Scientific American article for more.The warming in the Arctic already appears to place it now above any period in past human history. "The Siberian Shelf alone harbours an estimated 1,400 billion tonnes of methane in gas hydrates, about twice as much carbon as is contained in all the trees, grasses and flowers on the planet". While physics argues that methane hydrates of the East Siberian Shelf can only slowly (in human terms) turn to methane gas (Archer 2013), it is uncertain how vulnerable to atmospheric release are any shallow ocean methane deposits in non-hydrate form. The rapid loss of Arctic sea ice is raising the insolation to the shallow ocean and temperatures could rise several degrees Celsius. Since the East Siberian Arctic Ocean bottom is only ~40m deep in many places, it could warm significantly. Is this likely to trigger a "methane apocalypse"? Methane hydrates should only have formed in pressures underground and undersea that correspond (at 0 Celsius) to 250 meters ocean depth, and thus far beneath the ocean bottom and beneath over 100m of sediments, which can conduct heat only very slowly. Heat will only be able to reach such depths over many centuries, and even if a large chunk of methane hydrate were to reach critical temperature, it must absorb the latent heat of formation before it can turn to gas and possibly enter the atmosphere. These facts argue that methane release from the Arctic will proceed slowly, and therefore much of the methane will have a chance to oxidize to much less potent GHG's of CO2 and water vapor. A good rule of thumb is that, over the long term, having carbon enter the atmosphere at methane doubles the greenhouse warming entering at CO2 directly. During some earlier interglacial periods Arctic temperatures were warmer than today and there is no fossil evidence of catastrophic methane release. At least a couple of times in the past 200,000 years, the Arctic has seen higher temperatures than now, with no large methane hydrate abrupt release. Slow release would be hard to measure, since it oxidizes on a few decades time scale.
To summarize: while the danger of catastrophic rapid methane release in the Arctic appears to be low, slow methane release is a virtual certainty, and is calculated to increase greenhouse warming by an additional 30% by itself. Note that slow release is less dangerous because the half-life of methane in the atmosphere is only ~10 years before it oxidizes into the less potent greenhouse gases CO2 and water vapor. This is why the time scale for methane release has a profound effect on the level of warming force delivered. It is many times greater if the methane is released very rapidly. Burning 10's of millions of years of fossilized sunlight in the form of oil and coal from the Carboniferous Period, as we are doing all in a geological instant, is applying a radiative forcing the planet that has few if any parallels in past paleoclimate. The destabilization of the Arctic Ocean clathrates and rapid melting and release of methane from the permafrost cannot be completely ruled out yet.. But if it indeed happens, then the danger to Earth is much worse than any described here so far. And if we are to consider centuries and millennia for Earth as still being "short" geologically, then there is plenty to worry about. For example, the Paleocene-Eocene Thermal Maximum, and the end Permian Extinction, both involved, at least in part, massive methane release over geologically short time scales.

“The concept is actually relatively new,” says Kevin Schaefer of the National Snow and Ice Data Center at the University of Colorado in Boulder. “It was first proposed in 2005. And the first estimates came out in 2011. Indeed, the problem is so new that it has not yet made its way into major climate projections", Schaefer says. “None of the climate projections in the last IPCC AR5 report account for permafrost,” says Schaefer. “So all of them underestimate, or are biased low.” To clarify, since, by the very conservative modeling of the IPCC, the Arctic Ocean thaw wasn't expected until the end of the 21st century, these effects are not included in their 2007 IPCC AR4, nor 2014 AR5. Far from being too "alarmist", the IPCC is not being alarmist enough. Politics within the IPCC government officials who must sign off on official statements, guarantee this will likely always be the case. Will these coming tragedies be enough to generate political action in spite of this political inertia? If we wait, by then, of course, it will be far too late.

What are the oil companies doing about this rapid thawing of the Arctic? They're scrambling to claim vast stretches of thawing permafrost land and melted Arctic Ocean - FOR NEW OIL DRILLING. The "Tragedy of the Commons" has never, and likely will never again, be written so large on human history. Big oil is determined not to let their massive fossil fuels become "stranded assets". The Saudi's and OPEC refuse to prop up prices by lowering production and the shale "boom" has caused oil and natural gas prices to plummet in 2015. World production and even US production of oil continues high and higher (graph at left). Don't count on either moral conscience, or even a small carbon tax such as Citizen's Climate Lobby is hoping for, will do anything towards reducing the total CO2 burned into our atmosphere. Their attitude is to sell it and burn it as fast as possible. I would hope that any fossil fuel company executive involved in this would pause and consider what their children and grandchildren will feel about them, personally, for their actions.

We've been convinced since no later than 1990 that it is mainly human-caused CO2 emissions (with additional help from human-caused methane emission and cutting of forests) which are causing global warming, and it is the ongoing oil and right-wing sponsored denialist efforts which have paralyzed us for over 20 years now, and to this day, we see not only no reductions, but instead an acceleration of global CO2 emissions and atmospheric concentrations. In a recent paper discussion (2013), Hansen shows how the IPCC models under-predict sea level changes and why, ignoring important accelerating ice loss effects. He expects a "business as usual" scenario to result in many meters of sea level rise during the 21st century, and that if the defiant vow of Exxon to extract and sell all of its fossil fuel reserves (2014) comes true, the Earth will likely become uninhabitable by humans at some point. Studies (Gillette et al. 2011 Nature: Geoscience and references therein) are showing that CO2 emissions to the end of the 21st century lead, even with a complete end to all CO2 emissions at that time, to permanent, irreversible and ongoing sea level rises, and make for continued ongoing warming, ocean acidification, extinctions, and other environmental damage, for thousands of years. Zeebe et al. (2013 in PNAS, behind paywall but good summary here) have identified and quantified slow climate feedbacks, beyond the "fast" feedbacks usually considered. These slow feedbacks include ocean CO2

absorption ability, lower Earth albedo (reflectivity) as continental ice sheets melt, the loss of forests as they die under the coming long-term droughts, and others. Using paleoclimate data, they estimate the "fast+slow" climate feedbacks will cause a temperature rise of an additional 33% beyond simply the fast feedbacks (which operate over decades and centuries). They also find that these climate changes caused by man's burning of fossil fuels will accelerate as CO2 levels increase, and persist for at least ~20,000 years on up to ~200,000 years after fossil fuel burning stops. Solomon and other climate scientists have complained that this work is being used as an excuse for hopelessness and inaction, (published formally in Science and described here), as denialism morphs into fatalism, the one constant being a stubborn refusal to do anything, even though, in fact, action to stave off the worst, is possible. I and other scientists stress that these models assume only passive cessation of CO2 emission, not to active removal of atmospheric CO2. If we develop a commitment to atmospheric CO2 removal, then future climate scenarios can change for the better. Foster and Rohling (2013) find that "the current relationship (sea level vs. CO2) is sufficiently refined to imply that CO2 would need to be reduced significantly toward 280 ppm before any lost ice volume might be regrown (similarly over many centuries)". We are at 402 ppm today and rising rapidly. It now appears too late for the massive West Antarctic Ice Sheet. Two new studies (Rignot et al. 2014, and Joughlin et al. 2014) published in May 2014 find that the ice sheet, which sources 6 large glaciers (video) sitting over a shallow ocean basin, has now begun to collapse as the glaciers have now thinned enough to float above their grounding lines. The collapse (JPL video, NASA video, Yale video) is described now as "unstoppable", and these 6 glaciers alone will raise global sea levels a minimum of 4 to 10 feet over the coming century or two. Justino et al. (2014) show that the loss of the WAIS will have profound effects globally, not just in sea level, but in ocean thermohaline turnover, more rapid global warming, and a weakening north Polar Jet stream. Indeed, paleo evidence from ice-rafted debris (Heinrich events) on the ocean floor tells us that larger ice shelves than we have modeled, can break free and melt much more quickly than we had thought. Some part of the West Antarctic Ice Sheet subsurface melt may be further exacerbated by volcanism according to Lough et al. 2013. and Schroeder et al. 2014.

A team of 50 authors, led by Dr. James Hanson, has published (Hanson et al. 2016) a compelling case that the simple IPCC models are failing to capture the strong non-linear effects of ice sheet collapse, not just in West Antarctica as we now see, but Greenland and East Antarctica as well. Sea level rises of several meters are quite possible before the end of this century through these processes and as observed in paleo data under the influence of much lesser climate forcings than we are applying today. The resulting cold fresh meltwater causes large areas of stable low density surface water off Antarctica and south of Greenland which inhibit the global ocean circulation, preventing ocean radiant cooling, and driving the warmer subsurface waters against the ice sheets where they melt from underneath. We are already seeing these cold patches develop, and it is subsurface melting which has now already doomed the West Antarctic Ice Sheet, as described here above.. At global temperatures we are seeing today or in the coming decade or so, paleo data indicates the entire ocean conveyor can shut down, and this leads to a much stronger temperature gradient between the tropical Atlantic and Greenland, sufficient to drive "superstorms" capable of catapulting boulders weighing thousands of tons up onto beaches in the Bahamas, as evidence shows. Here is a good video summary of their large paper, by Dr Hanson.

While the atmosphere's absolute humidity rises, rainfall is predicted to drop over land, in general, and increase over the oceans and Arctic. A new paper (Famiglietti 2014 and discussed here and here) using the GRACE satellites quantifies the strong depletion rates of ground water over key agricultural areas of the world (including California's Central Valley) - "Groundwater depletion the world over poses a far greater threat to global water security than is currently acknowledged." Worse, the soil microbes necessary to fix nitrogen and maintain agricultural productivity are in strong danger of a tipping point in a hotter, drier soil (Delgado-Baquerizo et al. 2013 in Nature, and Wardle 2013 in Nature). Most plants are not carbon-limited, but nitrogen-limited in their growth. Studies indicate that at levels not affecting climate in a large way, many plants do benefit from increased CO2, but this rapidly shifts towards crippling existing plant species as climate itself changes more sharply beyond the plant's tolerance. That is the point we are at today. Food and water are the most essential commodities to support life. We need to double crop yields per acre by 2050 to keep up with projected population, but instead, there are worrying signs that crop yields, thanks to the Green Revolution, have peaked and have started to decline over the past decade. History shows wars and revolutions are the result of any threat to either of these essentials, and the global battles for food are what should be worrying policy makers (head of the World Bank 2014). It will be worse, for the fact that climate change will turn many of our staple foods into "junk food". With Exxon defiantly claiming they will mine all of their underground reserves and those yet to be discovered, these food and water wars would be devastating - Hansen et al. (2014 in Phil Trans of Royal Society) find that in such a "business as usual" scenario, most the Earth will become uninhabitably hot for mammals or most living things. You might be wondering why the hot-house climates of some dinosaur epochs are portrayed as lush with vegetation. If climate change happens slowly, as it has done for most of Earth's history, then species can evolve and optimize to the changing climate. But today's climate change is happening vastly faster than the slow processes of geology and solar insolation evolution governing most of paleo Earth's past climate changes. When climate change is this rapid, most species can't adapt; instead they die. As an example, a new paper in 2015 shows that seabird populations have declined by 70% since 1950 (Paleczny et al. 2015).

This isn't just theory. There have been at least two dozen instances of abrupt climate change, when global temperatures rose ~10F in a matter of decades due to transition from one point of quasi-stability (in a chaos theory sense) to another (Alley 2007). Now add to that - except for rare comet impacts or mega-volcanic explosions, Earth has never experienced the steeply rapid forcing to climate that we are doing today with fossil fuel burning. Climate change projected by the IPCC AR5 (2013) report under the business-as-usual scenario projects warming in the next 80 to 90 years to be bigger than the Paleocene/Eocene Thermal Maximum mass extinction event 55 million years ago... except changes today are happening 100 times faster those that caused the PETM. Transitioning into a new such climate regime today is not an unlikely tail-risk possibility. It's the path we are on, and it will be deadly to civilization, which is already precariously over-drawn in the way we treat resources. Ocean acidification is already happening at a rate higher than any other for the past 300 million years (Rogers et al. 2013). In a "business as usual" scenario, by 2047 the coldest months will be hotter than the hottest previous records in the pre-2005 period (Mora et al. 2013). Most of the population of Earth lives in China and Southeast Asia, which depend on the Himalayas for their water, and the Tibetan Plateau is warming at +0.3C per DECADE, 4 times faster than the global average. The effects on ice mass there is controversial, but appears to so far be low to moderate, vs. the erroneously large 7%/year quoted by the Chinese Academy of Sciences. At very high altitude, temperatures are still low enough that the more humid air can still provide more snow to offset the glacial melting, at least for now. But China's rivers are disappearing. 27,000 rivers have gone dry - northern China is said to already be in a water crisis, and climate change has only begun. It doesn't help, that China has now been discovered to be under-reporting their CO2 emissions.

Despite an increase in renewable energy use, fossil fuel burning is increasing even faster. As climate modelling and data get better and more detailed, the future is looking more and more frightening, and the urgency for immediate action was never greater. A good source for the latest, as of mid 2015, is Hansen et al. (2015).

And yet - it's worse. Professor Kevin Anderson describes how policy analysts are taking the science and deliberating spinning and misrepresenting projections in order to give the impression that we can reach politically acceptable targets with no sacrifice to economic growth. Professor Tim Garrett, using entirely different analyses linking thermodynamics to civilization itself, reaches the same conclusions. Halting climate change at +2C is essentially impossible, and even halting at +4C will be very difficult. But a +4C world will be one in which human civilization as we know it will almost certainly be impossible, and widespread breakdowns in societal order are likely, especially if we insist on a "have cake/eat it too" ideology.

The Human Meaning
The implications for national security have been clear even in the Bush White House... "Before climate change became taboo for Republicans, it was possible for even conservative politicians to have rational discussions about the subject. In 2003, under Donald Rumsfeld, former President George W. Bush’s defense secretary, the Pentagon published a report titled “An Abrupt Climate Change Scenario and Its Implications for United States National Security.” Commissioned by Andrew Marshall, who is sometimes jokingly referred to within the Pentagon as Yoda — and who was a favorite of Rumsfeld’s — the report warned that threats to global stability posed by rapid warming vastly eclipse that of terrorism. Some of the climate science in the report was flawed, but the broader conclusions were not. 'Disruption and conflict will be endemic features of life,' the report stated. 'Once again, warfare would define human life.' " (source)

Despite the public political posturings of carrying on the fight against climate change, even the supposed "good guys" in the Democratic Obama administration - John Kerry's State Department 's own analysis and plans call for abject failure not just worldwide, but in the U.S. as well.

Locally, climate change is expected to make most of the habitats in Santa Cruz County which are suitable for redwoods, will no longer be suitable by the end of the century (20min into this documentary). The deserts to the south of us will be marching northward, as they already are.

This, and oil corporations' response to the thawing Arctic makes me stand in awe. Awe of what some human beings are capable of doing - people such as the Libertarians who have convinced themselves of their intellectual and moral superiority. These aren't psychopaths escaped from prison, these are the most prestigious business leaders on Earth, determined to indulge their compulsion for short-term profits at the expense to all life on Earth for thousands of years and more, on what (by the evidence) suggests may well be only planet in the Galaxy which was capable of evolving intelligent life. Are the political/economic systems which grant power to (or allow to remain in power) such people really the best we can do, as the apologists of laissez-faire claim? This grossly negligent attitude on the part of business and political leaders towards all future generations has me stunned. I do not experience life the way I used to. This past decade I find myself questioning my most fundamental understandings of humankind. You may say that corporations have a fiduciary responsibility to their short-term oriented shareholders. Yet where do we see corporate leaders begging the legislatures to create laws which will force them to behave more responsibly while still operating on a level business playing field? Where do we see political "leaders" taking the initiative themselves? The answer to that is - virtually without exception - we see the opposite. We see lies and slander against the brightest and most honest minds we have. This speaks to me of moral character, not mere ignorance. If alien intelligence from elsewhere in the Galaxy ever arrives at Earth, I believe this will be their most shocking and baffling discovery - that it harbors a conscious thinking species which has produced incredible works of artistic beauty and deep insights into the nature of Reality, yet virtually everywhere and at all times in history continues to install (or tolerate) the most corrupt, stupid, and viciously greedy members of that species into positions of ultimate power. Why do we put up with this? The possible excuses and answers which I can imagine still pale against the magnitude of the issue.

We're going to be forced to find a way to actively remove CO2 from the atmosphere on a grand scale, regardless of emissions cutbacks and conservation, and do it as rapidly as possible, regardless of cost. There are only the barest beginnings of such an effort currently, with virtually no funding. Klaus Lackner estimated ~$200/ton, but House et al. (2011 in PNAS) find key flaws and that the true cost (in 2011 dollars) is likely to be about $1,000 per ton of CO2. Indeed, Lackner's business venture in this direction closed down in 2012. And now, in 2014, Lackner acknowledges costs are indeed more like $1,000/ton CO2. To put that in context, to remove enough CO2 from the atmosphere to bring it from 402ppm to 350ppm, would cost $56,000 for every man, woman, and child on the planet. That's assuming that the massive scale up will still allow a place to sequester it. Pumping it back underground may not be possible. It's highly questionable there are enough suitable geologic formations that can handle this and keep it sequestered. It's a spectacularly difficult undertaking, since the scale of the energy required to accomplish this is, by simple physics, comparable to the scale of the energy benefit fossil fuels have already provided by burning them. We see very little climate modeling which includes active atmospheric CO2 removal (perhaps because it appears so politically and technically unlikely). Even if atmospheric CO2 removal does become technologically feasible on a grand scale, remember we are not in radiative equilibrium, and remember that 93% of the greenhouse heating we have already done has been deposited into the oceans. Removing the excess heat may require removing enough CO2 from the atmosphere to cool it to the point it can act as a significant heat sink, re-freezing the permafrost, reversing the melting of Greenland and West Antarctica, and doing so on a short enough time scale to make a human difference. What kind of reverse climate change will that produce, realizing that temperature change over land is much stronger than it is over the oceans or the globe as a whole? To my knowledge, this has not yet been studied. Will humans tolerate their own short-term discomfort in a cooling climate, for many decades or centuries, so that future generations can once again have a stable climate and stable sea levels? So far, the evidence is that they will not.

And how will we summon the personal energy to accomplish these huge tasks? That, too, will be more difficult. Published research shows that once temperatures climb above 26°C (78°F), human work productivity falls by 2.4 percent with every degree Celsius of further increase. Picture sweaty, lethargic people trying to summon the will to get up out of their chairs and fight climate change.

Runaway Greenhouse Syndrome?
When tipping points are crossed, how far can the climate shift before a new quasi-equilibrium is reached? Venus has a size and gravity very similar to Earth. Back 4 billion years ago, when the sun was 30% less luminous, it is estimated that the climate of Venus was likely very much like the Earth - with oceans and perhaps the beginnings of life. But as climate warmed, rising water vapor compounded the CO2 greenhouse effect. Rising temperatures made higher humidity, raising temperatures further, raising humidity further, until the oceans turned to vapor, and solar ultraviolet light dissociated upper atmosphere H2O into hydrogen and oxygen. The oxygen bound with rocks and the hydrogen escaped into space, leaving a near pure CO2 atmosphere. If Venus had made limestone rock as living organisms have on Earth, then at temperatures of a few hundred Celsius, carbonate rocks would release their CO2 to the atmosphere, a process called "sublimation", and cause an additional runaway. After water vapor was completely destroyed, the water vapor greenhouse effect would stop and temperatures would stabilize near the observed Venus ground temperatures of 900 degrees Fahrenheit - the Runaway Greenhouse Syndrome. On Earth, is it possible that Arctic permafrost methane deposits could be released into our atmosphere, and the resulting rising ocean temperatures destabilize the vast methane hydrate deposits of the continental shelves? This does not look at all likely, the methane hydrates now believed to be buried to deep that surface heating could not penertrate to them in any human time scale. However, recall again that pound for pound, methane is ~25 (century) to ~100 (decade) times more powerful than CO2 as a greenhouse gas, depending on how rapidly it is released. The amount of methane hydrate in the continental shelf is not well known, but is believed to be vast. Carl Sagan warned of greenhouse warming on Earth in this 1990 video, when climate models and the understanding of physics was already advanced enough to justify single-minded determined global action to halt carbon emissions. Think about that as you watch this 4 minute video from Stephen Hawking and Carl Sagan. More recent quantitative research gives more reassuring answers as to whether we could trigger a runaway greenhouse by our fossil fuel burning. A runaway Venus syndrome is not at all the best estimate of climate scientists. Goldblatt and Watson (2012) find that we are unlikely to be able to trigger a runaway greenhouse, (but with the caveat that the behavior of clouds in "hothouse Earth" conditions is not well known yet, and so a runaway greenhouse cannot be absolutely ruled out). Additional evidence that we cannot trigger a runaway greenhouse is that CO2 levels have been much higher in the past, as high as 2000 ppm as recently as 100 million years ago. Even accounting for the dimmer sun a hundred million years ago (about 0.8% lower solar luminosity, which by a simplified greenhouse calculation (see here), corresponds to only ~0.5C lower equilibrium surface temperature, other things being equal), the higher CO2 would dominate the climate effect and yet did not trigger a runaway greenhouse.

Witnessing all this, my own personal feelings are indescribable, especially when I see people (fortunately rare and getting rarer) in educational positions betray their responsibility to tell the truth on this issue, while posturing as having "expertise in climate science" and posturing as advocates of science, when they are in fact supported by oil money. Elsewhere in my courses, when we put life on our planet in a cosmic context with possible other alien life forms, I have in the past cautioned some of my students for their facile denigration of the human species. We are, after all, demonstrably capable of greatness. But looking at this betrayal by so many in positions of trust and authority, and watching this great tragedy accelerate, I understand their helpless feelings of anger at how self-destructive we are being, I understand their frustration as we insist on placing the worst examples of our species into positions of political and business power. Now, I struggle not to share many students' cynicism about political solutions, and even what it really means to be human in the wider sense, and am not happy to be saying so.

Some have criticized my writing style on this subject as "pathologically negative" and off-putting. If the goal is to motivate effective action to address the future, is it best to leave realism-based gut-level human meaning out of the presentation and implications of the science? Scientists have been climbing a steep learning curve in trying to figure how to talk to non-scientists. I've argued that we have been TOO circumspect and cautious and conservative in our communications to lay people over the ~30 years we have been convinced of the seriousness of human-caused climate change. A paper by Harvard professor Naomi Oreskes agrees, as does this recent interview (2015) with glaciologist Eric Rignot, and finds that cultural factors have conspired to leave the lay person insufficiently alarmed, and the typical climate scientist too inhibited to be as blunt and emotionally connected to the human meaning as necessary. Yell "Fire!" in a crowded theater, and if your fellow theater-goers look around and do nothing, you're very likely to do the same.. We communicate not just by arcane abstract numbers, but by our emotional reaction to what they mean. If we are to communicate with the non-scientists, we must stop being so circumspect and communicate the meaning emotionally. An excellent interview with scientist George Marshall on psychology and communication in climate change is here., and the deliberate Pollyanna-ish misprepresentations of policy analysts as revealed by Tyndall Center director Dr. Kevin Anderson in 2015 . There are those who contend that, essentially, people must be pandered to, or they'll sink into despair. That the only path to a better future is evangelistic cheerleading that there need be no cost to civilization to a sustainable future. The "no cost" idea may have once been true, ~30 years ago, with massive efforts. Those warnings were ignored, and energy consumption and CO2 generation have skyrocketed since then, and the Third World is rapidly wanting the "good life" of the West, which requires vast energy consumption. And so, it is no longer true that we can avoid a wrenching future, or worse. The Earth will not heal. Physics shows that temperatures will not retreat, regardless of draconian CO2 cutbacks, and they are dangerously too high already. And so...

Can We Avoid The Worst of This Frightening Future?
Perhaps. But it that will require not only a complete cessation of human-caused CO2 emissions, but a vast effort to pull CO2 from the atmosphere rapidly enough to reduce temperatures and halt the polar thaw. There is no political appreciation of this fact, and even most of those who want to work for a better future do not appreciate this stark reality, still believing in the well-promoted idea of a +2C safe goal and perhaps the naive belief that reducing emissions will halt temperature rise and stabilize climate. Worse, even the (falsely described) "safe" +2 degree limit is being badly underfunded. Investments needed to keep the world below +2C are far below what's necessary, with investments decreasing in 2012 vs. '11, and again in '13 vs '12. The toothless Paris agreements of late 2015 do not change this significantly. However, I can't end this page without something more hopeful. Simply halting CO2 emissions, difficult as that is, is not enough. See this page for a bit on the current state of what we know about how to reduce CO2 emissions and remove CO2 from the atmosphere.

Also, this is a good place to head off any temptation to place my interpretations along with those of former University of Arizona biology professor Guy McPherson, who has many YouTube videos (for example) claiming that humans will be extinct due to runaway climate catastrophe as early as 2030. There are many deep flaws in his arguments, and some are outlined by Scott Johnson here. One of his key points too, is claiming that cloud physicist Professor Tim Garrett (University of Utah) has shown that industrial society is a massive heat engine whose heat will guarantee climate catastrophe. In fact, this is not fair to Garrett's excellent work on civilization and energy consumption in light of thermodynamic basics. While it's true that nearly all industrial energy produced ends up as heat (except for some which ends up as visible light that escapes directly to space), the contribution of human/industrial-generated heat is only 1% of the heat that we TRAP by our greenhouse gas production (Flanner 2009). Similarly, work by Wright and Schaller (2013) which was quoted widely in the media, argued that the Paleocene-Eocene Thermal Maximum (PETM) had a sharp spike in carbon emissions and resulting temperature rise globally of +5C in only 13 years(!), giving credibility to the idea of a "methane apocalypse". However, their interpretation rests on sediment layering which they interpret as annual - a weak argument. Zeebe et al. (2014) show that this is impossibly fast, mostly due to the large thermal capacitance of the ocean. Instead, the PETM excursion must have taken many centuries at least.

The best science says we're almost certainly headed for a long term crippling future, but not near term human extinction. Even societal breakdown (which certainly can't be ruled out for this century) shouldn't be assumed to result in human extinction.

Return to Climate home page