The warming of Earth is much more significant than we thought, because geologically speaking we are in the middle of an ice age recession, not a period of unchanging baseline temperatures.
“Until very recently in the history of Earth, humans and their activities have been an insignificant force in the dynamics of the Earth System. Today, humankind has begun to match and even exceed nature in terms of changing the biosphere and impacting other facets of Earth System functioning. The magnitude, spatial scale, and pace of human-induced change are unprecedented. Human activity now equals or surpasses nature in several biogeochemical cycles. The spatial reach of the impacts is global, either through the flows of the Earth’s cycles or the cumulative changes in its states. The speed of these changes is on the order of decades to centuries, not the centuries to millennia pace of comparable change in the natural dynamics of the Earth System.
The extent to which human activities are influencing or even dominating many aspects of Earth’s environment and its functioning has led to suggestions that another geological epoch, the Anthropocene Era…has begun.”
-Global Change and the Earth System: A Planet Under Pressure, quoted in Facing The Anthropocene by Ian Angus
In a recent entry titled “Always More, Always Worse, Always Sooner Than Expected,” I argued that the unending barrage of bad climate news and research revealed by even a cursory review of literature is almost always categorized as surprising and reflective of worst case scenarios; this consistent failure of excessive optimism should cause us to reevaluate our thinking about climate change with the aim of more accurately predicting and describing a process that is already underway and promises to be transformative for the planet and its most vulnerable inhabitants. Yesterday, another example of this phenomenon was found in Greenland and Antarctica, where ice sheet melt is currently in line with the UN’s most dire predictions:
Bad news, everyone. The melting of ice sheets in Greenland and Antarctica is on track to meet the United Nation's "worst-case scenario" forecasts, threatening millions of people worldwide with severe flooding each year.
In the damning study published in the journal Nature Climate Change, researchers from the University of Leeds in the UK and the Danish Meteorological Institute found that melting from Antarctica has pushed global sea levels up by 7.2 millimeters since the ice sheets were first monitored by satellite in the 1990s, while Greenland has contributed another 10.6 millimeters. On top of these glacial giants, there are also many smaller glaciers around the world that are also melting and fuelling sea level rise.
Altogether, the world's oceans are now rising by 4 millimeters each year as a result of thawing ice sheets. If melting continues to increase at this rate, the ice sheets could raise sea levels by a further 17 centimeters by the end of the century, exposing a further 16 million people to annual coastal flooding and destruction.
This, say the researchers, is almost exactly the "worst-case scenario" put forward in the United Nations Intergovernmental Panel on Climate Change (IPCC).
"If ice sheet losses continue to track our worst-case climate warming scenarios we should expect an additional 17 centimeters of sea-level rise from the ice sheets alone. That's enough to double the frequency of storm-surge flooding in many of the world's largest coastal cities,” Dr Anna Hogg, study co-author and climate researcher in the School of Earth and Environment at Leeds, said in a statement.
There are a number of reasons why the projections appear to have underestimated sea level rise, according to the researchers. For one, the existing models do not take into account clouds and cloud-formation, which help to modulate surface melting. Equally, many ignore short-term weather events, which are also likely to change in the face of further longer-term climate change.
There are likely a number of explanations for the tendency of scientists to underestimate the severity of anthropogenic climate change, including the well known Republican-led politicization of US government scientific and regulatory agencies and their infiltration by industry leaders and lobbyists as well as the vast, well-financed propaganda campaign by large polluters to muddy the waters around environmental issues. While these problems certainly need to be addressed, a more holistic approach among climate scientists might also be necessary, one that takes into consideration the interconnectedness of all systems and the unprecedented level of damage currently being done by the human race in virtually all arenas. One change we might emphasize is the fact that our world is not only warming significantly over the average temperatures of recent centuries, but it would have been in the process of cooling and emerging from the relatively warm interglacial period in the middle of the current ice age. In 2018, The Guardian summarized a recent study which tracked Earth’s temperature changes using pollen, finding that “humans reversed natural global cooling”:
What the authors found was very interesting. Using data from 642 sites across North America and Europe, the temperatures they found closely matched those expected from computer simulations. They found that throughout most of the Holocene period (the last ~11,000 years), the Earth was warming very slightly. Only in the last ~2000 years has the Earth been in a cooling period (which probably would have continued except that human emissions of greenhouse gases have now reversed the cooling).
The authors attempted to put the recent warming (last century or so) into context. They found that the recent temperatures are much higher than temperatures over the past 11,000 years. In fact, according to their calculations, 2016 was warmer than 99.41% of all simulated Holocene years.
This finding is profound. First of all, it means that human greenhouse gas emissions were easily able to overturn what should be a natural cooling trend. Second, the warming we have caused is far outside of the natural range. According to Dr. Shuman:
The major significance here is temperature across two continents over the last 11,000 years. The paper provides a geologically long-term perspective on recent temperature changes in the Northern Hemisphere and the ability of climate models, such as the National Oceanic Atmospheric Administration and National Center for Atmospheric Research (NCAR) models used in the study, to predict the changes. Climate simulations do a strikingly good job of forecasting the changes.
I would say it is significant that temperatures of the most recent decade exceed the warmest temperatures of our reconstruction by 0.5 degrees Fahrenheit, having few -- if any -- precedents over the last 11,000 years. Additionally, we learned that the climate fluctuates naturally over the last 11,000 years and would have led to cooling today in the absence of human activity.
What would the earth look like if humans hadn’t begun altering the biosphere centuries ago, and then greatly accelerated that process following World War II? According to geologists, we are currently in the midst of a more temperate period of an overarching ice age, whose resumption we are postponing by warming the planet through anthropogenic climate change. But we are not just forestalling cooling by lessening that trend, we are causing an overall increase in temperatures—without human activity, the climate would still be changing, not remaining static, so our impact is actually greater than if the temperature was in a long stasis. The planet is supposed to be cooling, not warming, and our influence on natural processes is all the more significant and damaging for it. To put it in perspective, the difference is between losing a significant amount of money on a bet and not betting anything at all.
The planetary cycles we are in the midst of disrupting have an almost incomprehensible scale—our influence on the earth is outsized and ought to require a responsible stewardship of these natural processes, but we have thus far shirked our duties entirely. Again from Ian Angus’ Facing the Anthropocene:
At the Amsterdam Global Change conference in 2001, the chair of the IGBP’s [International Geosphere-Biosphere Program] Scientific Committee, Berrien Moore, pointed out that cycles found in the Vostok ice core show a remarkably consistent pattern over hundreds of thousands of years.
The repeated pattern of a 100ppmv [parts per million by volume] decline in atmospheric CO2 from an interglacial value of 280 to 300 ppmv to a 180 ppmv floor and then the rapid recovery as the planet exits glaciation suggest a tightly governed control system with firm stops at 280-300 and 180 ppmv. There is a similar CH4 [methane] cycle between 320-350 ppbv [parts per billion by volume] and 650-770 ppbv in step with temperature.
The enormity of our changes to these cycles cannot be understated. Angus also quotes an article from Science titled “The Anthropocene is functionally and stratigraphically [the study of geological strata] distinct from the Holocene”: “For thousands of years global average temperatures were slowly falling, a result of small cyclical changes in the Earth’s orbit. Since 1800, increased greenhouse gases have overwhelmed the orbital climate cycle, causing the planet to warm abnormally rapidly.” Peter Brannen echoes this in The Ends of the World, noting that our epoch is taking place in the middle of what ought to be only a brief respite from the cold:
There have been at least twenty such balmy intermissions like our own sprinkled throughout the past few million years of our ice age. But unlike the many previous warm interglacials, civilization—and all of recorded human history—happened to arise during this one. Our few millennia in the sunshine are up, and if it weren't for us, we might be just about ready to leave this agreeable little interregnum and jump back into the ongoing deep freeze of the Pleistocene for 100,000 bitterly cold years. (Obviously, because of the ways humans have profoundly transformed the chemistry of the earth's oceans and atmosphere in only the past few decades, this regular schedule has probably been upended and it's not about to get colder anytime soon.)
If indeed the ice age was set to resume and is being postponed by human emissions, would this natural trend toward cooling act as a damper on temperature increases brought about climate change, or have we entirely upended the natural cycle? Another Guardian article discusses a 2016 Nature Climate Change study about the accelerating speed of our Anthropocene temperature increases:
The Nature Climate Change study didn’t just look at sea level rise; it also looked at global temperature changes. Earth’s sharpest climate changes over the past half million years have occurred when the planet transitions from a ‘glacial’ to ‘interglacial’ period, and vice-versa.
Right now we’re in a warm interglacial period, having come out of the last ice age (when New York City and Chicago were under an ice sheet) about 12,000 years ago. During that transition, the Earth’s average surface temperature warmed about 4°C, but that temperature rise occurred over a period of about 10,000 years.
In contrast, humans have caused nearly 1°C warming over the past 150 years, and we could trigger anywhere from another 1 to 4°C warming over the next 85 years, depending on how much more carbon we pump into the atmosphere.
What humans are in the process of doing to the climate makes the transition out of the last ice age look like a casual stroll through the park. We’re already warming the Earth about 20 times faster than during the ice age transition, and over the next century that rate could increase to 50 times faster or more. We’re in the process of destabilizing the global climate far more quickly than happens even in some of the most severe natural climate change events.
These rapid warming periods have had a profound destructive impact on planetary life when they’ve taken place, and our actions are already greatly magnifying and hastening these deleterious natural processes. Will this result in a slingshot effect in tandem with the many climate feedback loops already accelerating the process of warming, creating a both a short- and long-term annihilation of the biosphere? Short-term: sea levels rise as glaciers melt and lose albedo and coastal cities are flooded, biomass and biodiversity losses combine with soil degradation to deplete food supplies for billions of people, vast regions of earth become uninhabitable due to extreme temperatures, power grid failures and waves of desperate migrants lead to instability in the political system and inevitable fascist autocracy and mob violence…throughout all of this, storms, heatwaves, droughts and floods will be more common, adding compounding bursts of suffering. Long term: the one known planet capable of hosting life is rendered forever dead to all but the simplest life, a monument to one undeservedly influential animal who threw it all away because it was easy, lucrative, and ordained by a higher power.
The nightmare scenarios need not come to pass, even though some destruction is already both inevitable and ongoing. Massive systemic changes are necessary, far beyond any solutions offered by green technology such as carbon capture. A full, empowered extremist communist revolution complete with forced decarbonization, rewilding and reforesting, wealth redistribution (or distribution from the thieves who amassed it to its rightful owners), and vigorous environmental sustainability initiatives is the only hope. In addition to saving our civilization, this is a good idea to begin with, opposed only by self-interested capitalists and the ignorant subjects they were able to deceive by propaganda and culture war distractions.
If we fail to make these changes now, they will be made for us in very short order and in a very unsentimental way by the earth itself, which as the ice cores above show us, does not peacefully abide much in the way of disruption of its processes.
