Stephen Mulkey is an environmental scientist dedicated to developing undergraduate and graduate programming to build society's capacity for environmental mitigation, adaptation, and resilience. Mulkey was the president of Unity College in Unity, Maine from 2011 through 2015. His leadership and forward-looking vision resulted in Unity College being the first college in the U.S. to divest its endowment from the top 200 fossil fuel companies, and the first college in the U.S. to adopt sustainability science as the framework for all academic programming. Mulkey believes that higher education has an ethical duty to prepare generations of graduates for the extreme sustainability and climate change challenges of this century. After taking his PhD at the University of Pennsylvania, he spent over twenty years as a forest ecologist affiliated with the Smithsonian. Mulkey has served as tenured faculty at three doctoral granting universities.
The notorious Breakthrough Institute has been busy. Their director of climate and energy has been allowed by the editors of Nature to publish a critique of the use of RCP8.5 as BAU.* While it is true that many papers misinterpret RCP8.5 as being the worst case scenario and that this is equivalent to BAU, the authors of the RCPs recently reminded the climate community that RCP8.5 assumed maximum burning of coal , which is not what is happening and not likely to occur.
We have been aware of the misuse of RCP8.5 for quite a while, but the purpose of the commentary in Nature was to make the claim that BAU will lead to about 3.0˚C global average warming by the end of the century. Of course, this level of climate change would be nothing short of catastrophic and the scientific community is nowhere near reaching a consensus that this is would be the outcome of BAU. Moreover, the latest estimates of Equilibrium Climate Sensitivity suggest that we are on track to warm as much as 6˚C. To be sure, this result is being questioned by leading climate scientists such as Gavin Schmidt. Stay tuned to see what happens as the various modeling groups work out their differences and validate the models.
The problem with dismissing RCP8.5 is that one interpretation of the trajectory of warming indicates that we may be on this path or slightly higher. If so, what is the source of the additional climate forcing? This morning Michael Mann produced his review of the Nature article and notes that the spin in this commentary is not supported by the science. Mann points out the difficulty in assessing the track we are on, and more importantly, he emphasizes that we know almost nothing about positive feedbacks from the biosphere. Certainly these feedbacks are poorly constrained in projections, likely very large, and rapidly growing.
One good thing about the article in Nature is that it provides a brief explanation of the improvements in the scenario analysis that will be presented in the AR6. Under development is a subset of the SSP models (Shared Socioeconomic Pathways) that will function in a similar way to the RCP scenarios in the AR5. Although this represents a conceptual improvement, the new scenarios promise to be very complex. The big unknown in all of this is what humanity will do. Our economy will be the driver of whatever path we assume moving forward.
About the Breakthrough Institute
This organization got its start with an article entitle The Death of Environmentalism. The authors, Michael Shellenberger and Ted Nordhaus have since become the darlings of the business elite and they are featured regularly in the Wall Street Journal. Neither Shellenberger or Nordhaus has a terminal degree in any science, but they have apparent collaborations with conservative think tanks and conservative leaning scientists, such as David Kieth at Harvard who is a leading advocate of geoengineering and has financial connections to corporate development of this technology. Nordhaus is the nephew of William Nordhaus, who won the Nobel in Economics for his development of an economic model for assessing the impact of climate change (Many of us regard this model as worthy of scorn, rather than a Nobel).
The Breakthrough Institute has no academic or scientific staff to speak of, yet they seem to have an outsized credibility in the press. One of their recent “breakthroughs” is a white paper known as The Ecomodernist Manifesto. The most glaring flaw in their argument that we can have a “good” Anthropocene is that they ignore ecosystems and biosphere responses to environmental degradation and climate change. There is no mention whatever of the massive management efforts that would be required to realize this vision.
Perhaps most worrisome about the Breakthrough Institute is their insistence that we should burn fossil fuels generously as we develop other sources of energy. Their rationale for this is that energy-dense fuels such as coal and nuclear will result in less climate damage than the rapid development of renewables. Although there is some logic in this, their argument about energy-rich fuels should not preclude the development of renewables. Moreover, they ignore the social costs of further development of fossil fuels. Needless to say, the fossil fuel industry loves the Breakthrough Institute.
So what is the bottomline about RCP8.5? Depending on what the data show, it may be a useful surrogate for BAU, although this was not its intended purpose. We need to see what the data reveal moving forward. There is no doubt that the big unknown is biosphere feedback.
RCP = Relative Concentration Pathway; Developed to describe possible emissions scenarios in the IPCC Fifth Assessment Report (AR5). BAU = Business as Usual.
Recently researchers have noticed several areas where large amounts of methane are bubbling to the surface of the Arctic Ocean. The press has quoted one of the observers as saying that this is “terrifying.” Another recent report has declared that the Arctic tundra is now a net source of carbon emissions. Perhaps.
Has the Arctic passed a tipping point? Circumstantial evidence is pretty scary, but it needs to be put in the context of overall emissions from the Arctic biome. We need comprehensive inventories of these lands and waters to understand the extent to which these one-off events are truly cause for alarm. There is little doubt that the tundra is rapidly transforming, and there have been a distressing number of discoveries of such large gas eruptions in Siberia.
Make note of the Paleocene-Eocene Thermal Maximum (PETM). This was a spike of 5-8˚C in the atmospheric temperature about 55.5 mya. Officially the academic community does not know what caused the PETM, but increasing evidence from stable isotopes is compelling that it was caused by pulses of CO2 and massive releases of methane. Methane has an intrinsically high forcing ability and a relatively short lifespan in the atmosphere. It is interesting that the PETM lasted only about 200,000 years, whereas other forcing events that involved large amounts of carbon dioxide and methane persisted for much longer.
There is a lot published on the ecosystem disruptions in the oceans and on land that occurred during the PETM and it is a model for what is unfolding as we warm our atmosphere during this century. The impacts of the PETM did not result in one of the five mass extinctions, but many species went extinct and there was wholesale disruption of the Earth’s ecosystems.
Recently a commentary in Science by two leading experts notes that the Amazon forest is very close to a tipping point. Deforestation and burning of the forest is now synergistic will increasing frequency of extreme drought. As a source of humidity, i.e. the trees, is reduced, the hydrology of the entire Amazon Basin is shifting toward drier conditions. The outcome of this is the creation of savanna, which has far less carbon uptake potential than the rainforest. The region that we have always assumed would absorb CO2 from the air is now mostly impaired. Along the way to this new state it will release enormous amounts of carbon and is becoming a massive positive feedback to the climate system.
We live in interesting times. What continues to amaze me is that as a species we can quantify and understand in explicit detail how we are destroying the Earth’s ability to support the civilization that has made this awareness possible. It is surreal.
Even stranger is the magic of CO2. Carbon dioxide is necessary for life and over billions of years the Earth has developed a dynamic flux of carbon among atmosphere, rocks, and living systems. This is part of the rhythms of our planet in which changes occurring over millennial timescales provides the substrate for the evolution of species and ecosystems.
Without anthropogenic influences during the modern era, CO2 should exist in our atmosphere well below 300 ppm. We are at 411 ppm as I write this. The last time our atmosphere contained ~400 ppm was the Pliocene, about 3 mya, and sea level was at least 6 meters higher than it is now. It is a rare gas that nourishes us all, yet if there is too much of it even if relatively rare, it can disrupt the climate that made possible the development of civilization. During this decade we have repeatedly been surprised by the sometimes extreme responses of the Earth System to about 1˚C warming.
CO2 and the other non-condensing greenhouse gases are responsible for the radiant energy structure of the atmosphere that makes the overall temperature of the Earth consistent with life. If CO2 were to be zeroed out, that structure would collapse and the Earth would become icebound with an average temperature below -20˚C. It is true that water vapor, a condensing greenhouse gas, is responsible for about 70% of the greenhouse effect, but only if CO2 provides the radiant energy structure of the atmosphere to allow sufficient capture of heat in the layer of air where we live.
The bottomline is that CO2 is the master thermostat for our planet and it has a rather narrow range of setpoints that are consistent with our needs. All of civilization and agriculture developed during the last 8,000 years, the stable period known as the Holocene, aka The Goldilocks Climate, because it was neither too cold nor too hot. It is entirely possible that the development of civilization is simply a one-off that may be just a blip in the unfolding evolution of the Earth System.
Amazingly, we understand these things about our planet even as we wreck it.
It is obvious that all weather now occurs in a human-altered climate. Thus, the question is not if a weather event has been caused by climate change, but rather which features of that event are attributable to climate change. Attribution is a rapidly growing branch of climate science that is showing us how features of extreme weather, floods, droughts, and fires are likely connected to climate change. As much as 30 percent of the mortality associated with the European heat wave of 2003 is attributable to climate warming.
Hurricane Dorian is indicative of how the features of cyclones can be attributed to anthropogenic climate change. Such attribution also applies to aspects of hurricanes Harvey, Florence, Irma, Michael, and superstorm Sandy. As reported last year by the National Science Foundation hurricanes worldwide are becoming slower, wetter, and stronger. The science about hurricanes is becoming increasingly definitive. It seems clear that such storms will be part of our future on the Atlantic coast of the United States.
The slowdown is attributed to the general weakening of atmospheric circulation in the tropics, where hurricanes form, and in the mid-latitudes where hurricanes often make landfall. The reduced translational speed has occurred worldwide and may be associated with the general weakening of the temperature gradient between the Arctic and the equator. In effect, the slowdown is being driven by Arctic Amplification, which is the more rapid and extensive warming of the regions closer to the north pole. Cyclones in most ocean basins have slowed down 17 percent relative to 1944–2017. Dorian’s forward speed was about 1 mile per hour when it effectively stalled over the Bahamas causing devastation of Abaco and Grand Bahama.
This slow-down is partly to blame for hurricanes becoming wetter. Slow-moving storms can acquire more water as they move over hot oceans. Moreover, the atmosphere holds about 7 percent more water vapor with every 1˚C warming. The atmosphere has warmed about 1˚C since preindustrial times and there is more energy and water vapor aloft. This energy is dissipated as extreme weather. The enormous amount of precipitation carried by Harvey and Florence is testimony to this reality.
Of course, the general strengthening of hurricanes is directly related to warming oceans and sea surface temperatures. It is arguable that our oceans are warming far faster than they have since the Pliocene, 3 million years ago, which was the last time CO2 concentrations exceeded 400 ppm and sea level rise eventually exceeded 6 meters. More than 90 percent of anthropogenic warming has occurred in the ocean. A study published in January 2019 showed that the warming of the oceans has been 30 percent greater than that reported in the latest IPCC report (2014).
Although there have been five Category 5 storms in the Atlantic in four years, an unresolved question is whether hurricanes will become more frequent as the Anthropocene progresses. For many of us who live near the Atlantic coast the answer to this seems obvious, but only time will reveal if the recent pattern is statistically robust. Many hurricanes before 1900 likely went unrecorded. The satellite era allowed us to track storms only since the mid-1960s and we have been using the Saffir-Simpson index for rating storm power since 1974.
An additional feature that is likely attributable to climate change is the rate of hurricane intensification. Wind shear can diminish hurricane power and speed of intensification. A recent paper showed that because of climate change wind shear is diminished as hurricanes enter the northern Caribbean and approach the Atlantic coast. This has resulted in an increase in the speed of intensification of recent hurricanes in the Atlantic. Such rapid intensification was a feature of hurricane Michael, which went ashore as a category 4 and utterly devastated Mexico Beach, Florida.
Given the reality of our future it is critical that we assess how we can proactively adapt to reduce the impact of extreme weather events. Although state and federal officials are responsible for warning us and providing relief after devastation has been wrought (assuming funds are not depleted), it is communities that have the greatest ability to take action to reduce the loss of property and life. The community is where the impacts of climate and ecosystem disruption are experienced, and it will be the front line of adaptation to these impacts. Such proactive adaptation is far less expensive and disruptive than reactive adaptation.
Communities can do many things to reduce the impacts of extreme events. For hurricanes, it is essential that we move homes and businesses out of harm’s way. Storm surge is amplified by sea level rise as exemplified by the surge from superstorm Sandy which hammered parts of the Atlantic coast of New York. Analyses of options in response to sea level rise result in the inescapable conclusion that strategic retreat from the coast is necessary. We should begin retreat now rather than deal with the enormous expense of cleaning up the mess after disaster strikes.
Sea walls and pumps won’t do the job and they are certainly not cost effective. The recent installation of pumps to counteract coastal flooding in Miami will buy precious little time and is probably a waste of money. Insurers are quietly withdrawing from insuring coastal and near-coast properties, especially for the Florida Atlantic coast. A study published last week in Nature Communications showed that the compound effects of sea level rise and increased hurricane power by the end of the century will result in the historical 100-year flood level occurring annually in New England and the mid-Atlantic coast. In the southeast Atlantic and Gulf the return rate of such floods will be every 1–30 years.
Perhaps as important as controlling where homes and businesses are built is the human infrastructure and scenario planning necessary to protect citizens during extreme events. Studies of Sarasota Bay provide a daunting scenario in which a category 4 storm sweeps ashore and devastates the high rises close to the bay. Many of the properties in this region are occupied by an aging population without access to independent transportation. The city and the county must continually revise plans to evacuate this population when a hurricane becomes imminent. As Sarasota County officials will tell you, this will be a herculean task that will require extensive coordination among overlapping jurisdictions in the region. Following the devastation of Dorian more than 70,000 are homeless and thousands from the Bahamas have become climate refugees.
Community organizations and non-governmental organizations must develop the capacity to coordinate proactive adaptation and plans with city and county agencies. Such planning is indispensable when an emergency arises. To be sure, our warning systems now provide ample lead time for a variety of coordinated efforts among organizations and government. Even though Dorian failed to make landfall along the Florida coast, the preparation that ensued from the warnings would have been indispensable had such landfall occurred.
The financial imperative of development must not be allowed to hijack realistic plans for proactive adaptation. An example of this is the long battle between citizens and deep-pocket developers who wanted to build Green Diamond, a billion-dollar development on the Congaree River floodplain in South Carolina. Fortunately, a coordinated effort by an unlikely coalition of citizen groups and concerned government officials stopped this development just before there was massive flooding in this region. In Florida a similar nightmare scenario has played out as developers have built with reckless abandon in several regions near the coast. We must make plans based on future projections, not on historical precedent.
Because of pressure from financial interests and politicians interested in short-term gain, the US is behind other countries in efforts at proactive adaptation. As reported in Science, bans on rebuilding in the path of storms and floods have been implemented in Australia, Germany, Japan, New Zealand, and the Philippines. Colombia, India, and Mozambique require resettlement after disaster to pre-identified safe locations. Governments have engaged in acquisition of vulnerable property in Colombia, Japan, Netherlands, New Zealand, and somewhat in the United States. Such acquisition is demonstrably less expensive than paying the bill after tragedy strikes. Some communities in Australia, China, Fiji, India, and Vietnam have been completely relocated.
Although there continues to be rather meaningless academic debate about the use of the term Anthropocene, there can be little doubt human actions over the last two centuries have profoundly altered the Earth. Future generations likely will be affected for millennia. If we stop all fossil emissions the return of the climate to something resembling the putative normal conditions of the 20th century will require hundreds to thousands of years through natural processes. Today you have experienced the most stable climate that you will ever experience for the remainder of your lifetime. Throughout my teaching I ask my students to accept the reality that active management of our climate and biosphere will be required for so long as civilization is to exist on Earth. We best get to it before the damages are so great that we can no longer stabilize the Earth System.
“The IPCC report demonstrates that it is still possible to keep the climate relatively safe, provided we muster an unprecedented level of cooperation, extraordinary speed, and heroic scale of action.” — Mario Molina. 2018. IPCC Nobel Laureate
Science does not blink. The special report issued by the IPCC in October 2018 is unequivocal in its warnings. We are out of time to take action to reduce fossil fuel emissions. We must engage in steep and immediate reductions in emissions if we are to keep the global average temperature from exceeding 2˚C by the early part of the second half of this century. The popular discourse about how many years we may have remaining to take this action is immaterial to whether we might achieve this. Given the current administration’s aggressive repression of science and the denial of the need to address this gravest threat to civilization since we wandered out of Africa, it is very unlikely that we will mount such a massive global effort with the necessary urgency.
But, certainly despair is premature, you say. There are now many countries, mostly small ones, that are committed to zero carbon emissions in the near term. Despite political resistance by utilities and the fossil fuel lobby, renewable energy is developing rapidly in Europe and some states of the US. Innovation in grid management and power storage have removed the often ridiculous arguments that renewables are unreliable because wind and sunlight are intermittent. My colleagues point to progress in the largely commercial renewable energy sector and declare that we will be mostly carbon free by 2050.
Terrific, but “mostly” doesn’t cut it, and mid-century is too late because a lot of damage will have been inflicted on the biosphere. There is a 30 to 40-year time lag in the Earth System after fossil emissions cease in which positive feedbacks and ocean heat transfers continue. These continuing impacts are nonnegotiable. Most of the scenarios used in the Paris Agreement assume a temperature overshoot during mid-century and that subsequently technology will be used to remove carbon dioxide and achieve “negative emissions.” As McKibben has said, “winning slowly is the same as losing.”
Staying at or below 2˚C warming during this century does not guarantee that we will avoid damaging climate change. The putative guardrail of 2˚C was agreed on at the Copenhagen 15th Conference of the Parties as a last-ditch compromise to salvage a positive outcome of this disastrous meeting of nations. There is no scientific basis for the notion that this is a safe level of warming. The present warming above pre-industrial is ~1˚C and features of several recent extreme events can be attributed to climate disruption. It will get worse. If you are alive today, you have already experienced the most stable climate that you will ever experience in your lifetime.
If all signatories to the Paris Accord from December 2015 meet their voluntary cuts, we will realize between 3.0 and 3.5˚C global warming by the latter part of the century. The impact of this warming on positive feedbacks from living systems is presently unknowable, but will likely be catastrophic. This amount of warming will result in an acceleration of climate disruption that will make conducting the affairs of civilization increasingly unmanageable.
At 3˚C we can expect widespread disruption of ecosystems and amplification of emissions from natural sources. The phenomenon of Arctic Amplification, whereby warming is more rapid and more extreme in the far north, will enhance positive feedbacks from melting permafrost, resulting in even more warming. The vast Amazon Basin is already close to a tipping point and, rather than acting to remove carbon, it will become a net source of carbon to the atmosphere. We can expect accelerating sea level rise, and an unknown but likely steep increase in the frequency of extreme climatic events such as severe drought, more and bigger fires, more and stronger cyclones, and more extreme precipitation.
The impacts of a 3˚C world on public health will be manifold with emerging and re-emerging infectious diseases driven by habitat destruction and climate warming. Warming will make cities in India seasonally uninhabitable and water supplies will be increasingly limited in the Hindu Kush Himalaya, where snow and ice melt serve over 2 billion people. The public health impacts of cyclones and flooding will continue to overwhelm our resources for repair and recovery. The UN expects tens of millions of climate refugees and it should be obvious that millions will die. The political disruption from this is difficult to contemplate. No nation has policies or infrastructure in place to manage such a tidal wave of desperation.
Without significant mitigation, our current emissions trajectory will result in 4–6˚C average warming by 2090. This degree of warming will end civilization for most of humanity. Crop production for a large population will be out of the question. All we have to do to achieve this result is to keep doing what we are doing.
Optimists continue to support the notion that we may be able to derail this trajectory. I hope the glass is indeed half-full, but it seems clear that moving the corporations and the government of the largest consumer economy will not happen in time. The hardest question that I get when I present climate science to the public is often from a young person who wants to know, “Should I have children?” Of course, I refuse to offer my opinion on such a personal choice, but I encourage them to consider the pace of social change in the context of what we know about climate disruption. They may choose to have kids anyway, but at least they will know what they are up against.
It is hardest for me to accept the naked immorality of this period in our history as a nation. In 2018, slightly more than half of the emissions residing in the atmosphere had come from the United States in some form. Present annual emissions from the US may rank second to that of China, but because we import much of our consumer goods from other countries, the emissions from their production and transport should appear in our debit column. If morality means anything, the United States has a moral obligation to lead in making this right.
My generation of baby boomers has a personal moral obligation to the current generation facing this daunting future to offer every assistance that we can. This includes the unmerciful dismantling of the fossil fuel industry and the associated economy. There is no doubt that a clean economy can replace this self-perpetuating abomination. We owe it to our kids to undertake this urgent task, regardless of whether we can stay below 2˚C.
The economist and Nobel Laureate, William Nordhaus, has stated that “there is no solution to climate change that is not a market solution.” Such narrow thinking got us into this mess, and it is worthy of scorn rather than a Nobel. Instead of insisting on a market-based solution, I suggest that we simply do the right thing and deal with reconfiguring the global economy as necessary.
The economy must serve humanity, not the other way around. We can invest in retraining generations of workers who presently participate in the fossil fuel economy. An alternative version of a clean sustainable economy that provides a safe and just future for humanity has been developed by such thinkers as Kate Raworth at Oxford. We can do far better, if we choose to.
Given that we are out of time and that the degree of necessary change is unlikely in the near term, this leads me to ask what we should be doing. Should we give up?
There have been moments when I considered buying a big-ass RV and traveling around to see our magnificent continent before our ecosystems transform. I am partial to glaciers and mountains. Perhaps there are a couple of decades that I could enjoy myself before age and the planet blow the whistle on my time on the field.
Thomas Berry has written that every generation has their Great Work. My father went ashore at Normandy, and his generation’s Great Work was the preservation of liberal democracy. They succeeded, if only for a time.
The Great Work of my generation has been to manage climate and biosphere disruption. We have utterly failed.
Perhaps our most important task is to prepare the current generation of young people for the changes that are coming and to give them the tools and infrastructure to mitigate the challenges that will result. In addition to working to reduce carbon emissions, the work for my generation is twofold. First, we must realign our secondary and higher education institutions to provide students with the facts about their future and the life skills to live in a post-consumer economy.
In the US many of these skills can be developed through the extensive system of community colleges. Sustainability should be central to the curriculum during the first two years of post-secondary education. All students should be required to have a minimum level of ecological literacy before graduation. This means that they will understand basic processes such as the carbon cycle, ecosystem services, and renewable energy production, and how disruptions of these will affect their lives.
In order to respond to the needs of our children and future generations, we must resurrect the doctrine of the Public Trust. This idea dates from ancient Rome and posits that certain functions and resources should be held in trust by government for the public good. Education at all levels must be rescued from its capitalist purgatory and refinanced as part of the Public Trust. Call this Socialism if you wish. I am all in.
Secondly, we should develop an extensive understanding of the changes that are likely to affect communities, including explicit projections of factors such as hurricane storm surge and the probability of compound heatwaves and multiple crop failures. The community is the front line of impacts and adaptation to the disruptions heading our way. As we work to reduce emissions, we can prepare the next generation to survive and even thrive in such a world, but we need to invest in the social sciences and the human infrastructure necessary to develop realistic scenarios for defined geographic regions.
What should the community of Daytona, Florida, expect by 2050? How about the changes that are likely to affect Wichita, Kansas, or Mumbai, India, or Bogota, Colombia, or Lagos, Nigeria, or Anadyr, Siberia? Big or small, all communities need expert scenario analysis and risk assessment. Our local and state governments can take the lead in developing these scenario analyses and we should demand that they do so.
The order of day by midcentury will be the maintenance of energy, food, and water security. Without the appropriate return on investment the business sector is unlikely to provide the resources and innovations needed to protect our communities. Maintenance of essential services must not be derailed by greed and business imperatives that require economic growth at the expense of additional carbon emissions and social equity. Central to keeping this process from being owned by corporations is the need to develop the civic structures and processes that ensure the democratic rule of the people of these communities.
As the ride gets bumpy, we must have in place processes and people that protect the common good and the ecosystems that we depend on. We should not look to the private sector for salvation. Corporations will never have such concerns as part of their imperative to increase shareholder value. At best, they are amoral, and at worst they are usury of the public good. For many corporations, their very existence and use of public resources constitutes a moral hazard.
Perhaps you find my thesis too grim to accept. Certainly we must continue to reduce carbon emissions regardless of the likelihood that we can alter the near term trajectory. I fervently hope I am wrong, but the science suggests that at minimum it is not only prudent but necessary that we develop plans and infrastructure for future generations. Gee, what would happen if we made our planet and society better, and somehow climate and biosphere disruption turned out to be mild?
Fat chance, but I propose that we invest in our kids no matter what.