Evolution is a tightly coupled dance, with life and the material environment as partners. ~ James Lovelock
Climate is one aspect of an evolutionary planetary gyre, both as self-regulating and self-perpetuating via feedback loops. These dual dynamics are characteristic of systems subject to self-organized criticality, where a wicked 2nd derivative – too much change too quickly – causes a breakdown in the existing range of “normal.”
With the warming the world has already experienced, we can see very clearly that a difference of 0.5 °C really does matter. ~ Swiss climatologist Erich Fischer
Nonlinearities can rapidly change weather conditions, so you get more abrupt changes. ~ Dutch climatologist Dim Coumou
Climate change is happening faster. ~ American climatologist Bryan Thomas in 2019
The most important fact about climate is that it occurs as a trend. Average surface air temperature over the last billion years shows this.
Perhaps the 2nd most important fact is not a fact at all. It is that little is known about the climate gyre; understandably so, because climate is a product of a planetary system of mind-boggling intricacy that operates on a time scale far longer than human experience.
At every point, as our knowledge increases, we’ve always discovered that the climate system is more sensitive than we thought it could be, not less. ~ American paleoceanographer Maureen Raymo
The threshold of hothouse Earth could be at a temperature rise of ~2.0 °C above preindustrial, locking in a continuing rapid pathway toward much hotter conditions. This pathway could not be reversed or substantially slowed. ~ American chemist Will Steffen et al in 2018
So much is happening at the same time and at a faster speed than we would have thought 20 years ago. We’re heading ever faster towards the edge of a cliff. ~ Swedish climatologist Garry Peterson in 2018
You don’t know how close to the cliff you are until it’s too late. ~ American ecologist Heather Lynch
Looking at the peaks and troughs of global temperature over the past billion years ushers the obvious question: what caused the turnaround? In most instances the answer is not known. Sometimes a cataclysmic event caused a climate reversal, but more often a shift in the climate gyre came from the self-regulating biosphere of Earth: what James Lovelock called Gaia.
◊ ◊ ◊
The warmth of the Sun was 30% weaker when the planet began hosting life 4.1 billion years ago (BYA). But Earth did not freeze over.
Internal heat generation made for a liquid ocean that covered the planet. Water has a lower albedo than land. The early global ocean absorbed much more thermal energy from the Sun than today’s continents ever could.
Water vapor and clouds held the warmth in. It helped that the air had a substantially different composition.
Back then, CO2 was the predominant atmospheric gas. Cyanobacteria evolved photosynthesis 3.6 BYA to take advantage of the bounty: consuming carbon dioxide exhaling oxygen as a waste product. This gaseous exchange eventuated in conditions favorable for aerobic animals to arise 800 million years ago.
Trading atmospheric CO2 for O2 had its repercussions much earlier than the coming of critters. A modest oxidation triggered an explosive growth in mineral diversity on Earth. The so-called Great Oxidation Event began 2.45 bya, fostering 2,500 new minerals: over half of the 4,500 minerals now extant. These minerals were later instrumental in fostering terrestrial life.
The world iced over 2.4–2.1 BYA during the Huronian glaciation. It is the earliest-known glacial period. There were several others in the eons that followed, most notably 800–600 MYA: a time termed Snowball Earth, when Earth shivered through 4 of the most severe ice ages in its history.
Owing to variations in orbit around the Sun, Earth naturally cycles between glacial periods and warmer interglacial periods. A cyclic cooling period halted after the advent of agriculture. Carbon dioxide levels started to rise 7,000 years ago. Methane emissions began going up 5,000 years ago.
Early farming helped keep the planet warm. ~ American paleoclimatologist William Ruddiman
Keeping the planet balmy with a bit of agriculture was not a bad thing, given Earth’s tendency to chill. But the explosive exhaust of industrialization was something else altogether. Waste heat and gaseous egest, mostly from machines, produce prodigious amounts of greenhouse gases. Industrial-era warming commenced globally as early as the mid-19th century. It is no small irony that the combusted fuels generating emissions come from fossilized plants: long-dead benefactors suborned.
Historically, plants helped keep the world cool and well oxygenated. They will be sorely stressed by the rising heat, caught between the dilemmas of carbon starvation and hydraulic failure.
When conditions get hot and dry, plants conserve moisture by closing their stomata, which are the pores that let plants breathe: absorbing CO2 and cooling themselves via evaporation. Closing stomata means not taking in CO2. If that goes on too long, a plant starves from lack of carbon.
Even with stomata closed, plants still uncontrollably lose water when it’s hot. Hydraulic failure from lack of water poses as great a threat as carbon starvation.
Along with microbes and plants, humans have had an outsized effect on Earth’s evolution. One consequence has been to change the climate. Unlike microbes and plants, man-made pollutants have wrought a tipping point that has turned into an extinction event. Earth has not had a “cooler than average” month since December 1984.
The unnatural habitat of man is illustrated by cities. The only other animals (beside humans) are either inconspicuous, domesticated, caged, or considered pests. With the exception of designated “green spaces” that comprise a small fraction of urban land, the only plants are potted.
Even the temperature is affected. New York City is often 3 ºC warmer than nearby countryside.
More self-destructively, urban air quality is unhealthy, and the water commonly contaminated. People simply seem unable to live in large numbers without severe environmental degradation.
Extreme weather has already become more common. Heat waves are more intense. Mid-latitude westerly winds have strengthened. Tropical cyclones are more powerful.
Droughts and desertification are worse in some parts of the globe, while precipitation has intensified in others. These have already impacted food production: a trend that will worsen in a nonlinear way.
We are witnessing is major hydrologic change. There is a very distinctive pattern of the wet land areas of the world getting wetter, in the high latitudes and the tropics, and the dry areas in between getting drier. Within the dry areas are multiple hotspots resulting from groundwater depletion. ~ American hydrologist James Famiglietti in 2018
Climate change does not merely change weather patterns. It also changes the flow of weather itself.
By altering global air patterns like the jet stream, a warming planet can cause weather to become more stuck in place. Whether drought, downpour, heat or cold wave, a weather pattern tends to persist.
The current global warming rivals the Paleocene-Eocene Thermal Maximum (petm), which occurred 55 mya. During the petm, global air temperature warmed ~7 °C in 10,000 years. Warming now is even more extreme, both in temperature rise and pace. Earth’s thermal dynamics exhibit self-organized criticality in warming related to greenhouse gas release. A tipping point for acceleration was reached in 1940.
The gyre of climate change that has been experienced to date is only going to disruptively intensify. The largely temperate world that mankind enjoyed in its middle age is being replaced by a feedback of environmental hostility.
The most obvious effect of climate change appears on the thermometer. The weakening of the polar vortex spells colder winters in the northern hemisphere, at least for the next decade or so. But the dire thermal throttle is heat.
Exposure to extreme wet-bulb temperatures will rapidly increase throughout the 21st century. ~ American atmospheric scientist Ethan Coffel et al
The wet-bulb temperature is how a temperature feels. Humidity makes a big difference. Muggy heat is more oppressive than dry.
Mammal bodies cool by sweating: sweat evaporates off the skin, wicking away excess heat. This evaporative cooling technique fails when the air is already moisturized. When cooling conks out, body core temperature rises beyond the narrow tolerable range, leading to lethargy, organ failure, and death.
The effects of heat stress will fall hardest on hot and humid regions. ~ Australian climatologist Steven Sherwood
Large swaths of the tropics, the Amazon, southern areas in the Mideast and Arabian Peninsula, northern India, the eastern US, and eastern China, will suffer increasingly severe humid heat waves in the years to come. The early death tolls will be highest in those areas with growing populations and scarce cooling infrastructure, notably coastal west Africa and northeast India.
The tropics transition to an almost constant heatwave state with just a 2°C rise. ~ Australian climatologist Sarah Perkins-Kirkpatrick
By 2100, global surface air temperature average will have risen by at least 4 °C above the preindustrial level (at the beginning of the 19th century). Humankind won’t survive that.
We are in deep trouble with climate change. ~ United Nations Secretary General António Guterres in 2018
As of 2017, the climate models that best fit the current trend are those which show the fastest global warming, with surface temperature 4.5–5.0 °C above the preindustrial level by 2100. A 2018 study, focused on climate model shortcomings, indicates that current estimates underestimate global warming and its consequences by a wide margin.
Observations of past warming periods suggest that a number of amplifying mechanisms, which are poorly represented in climate models, increase long-term warming beyond climate model projections. Model-based climate projections may underestimate long-term warming by as much as a factor of 2. ~ Swiss climatologist Hubertus Fischer in 2018
Earthworms illustrate the deficiencies in climate models.
Earthworms play an essential part in determining the greenhouse-gas balance of soils worldwide, and their influence is expected to grow over the next decades. ~ Dutch soil scientist Ingrid Lubbers et al
Taiga is the Earth’s largest land biome, comprising 29% of the world’s forest cover. Boreal forest is a nearly continuous belt of coniferous trees across northern North America and Eurasia. At least 20% of the carbon that cycles through the world passes through taiga.
In the past, forests were the great terrestrial carbon sink. That is rapidly changing, as the carbon stored in soils is released.
Taiga has special soil. In warmer climates, the floor of a typical forest is a mix of minerals and organic soil. In a boreal forest, those components are distinct, with a thick layer of mosses, fallen wood, and rotting leaves on top of the mineral soil. The spongy organic layer holds most of the carbon stored in boreal soil.
As the world warms, earthworms have been migrating north into taiga, where these worms have been relatively scarce (compared to the soils in temperate forests). Most of the earthworms heading north are ones that eat leaf litter but don’t burrow into the soil.
Even though worms themselves are tiny and don’t individually seem to constitute a threat, considering how many of them there are, they’re very important organisms. ~ American soil scientist Adrian Wackett
The impact of invasive earthworms is expected to be intense: reducing forest floor carbon 50–94% over the next 4 decades, thereby accelerating global warming in a way that no current climate models anticipate.
Environmental devastation from the rapid change of even the best-case scenario will be severe. Current estimates are likely to be exceeded, with global surface temperature rising 8 °C, and possibly more, by 2100, according to a 2018 study focused on cloud cover which isn’t considered in current climate models.
Global warming is accelerating. ~ Chinese atmospheric scientist Yangyang Xu et al in 2018
The faster the world hots up, the sooner humanity goes extinct. It will be a miracle of ingenuity if humans are still around in the 22nd century (after 2100). Civilization is more fragile, and hence survival more tenuous, than generally acknowledged. Living is difficult. Dying is easy.
All across the world, in every kind of environment and region known to man, increasingly dangerous weather patterns and devastating storms are abruptly putting an end to the long-running debate over whether or not climate change is real. Not only is it real, it’s here, and its effects are giving rise to a frighteningly new global phenomenon: the man-made natural disaster. ~ Barak Obama in 2006
5-6 degrees of global warming is enough to wipe out most life on the planet. ~ Italian ecologist Giovanni Strona
The Mekong River Delta
The Mekong River, natively known as the “mother of water,” flows down from the Himalayas, the mountain range that forms the top of the world. The Himalayas is one of the youngest mountain ranges, formed by the Indian subcontinent shuffling north and slamming into Eurasia.
The Himalayas hold the Earth’s 3rd-largest hoard of ice and snow, after Antarctica and the Arctic. Many rivers flow from here, fed by snow melt off the mountains and heavily augmented by seasonal rainfall. 70% of the rivers’ waters eventually wash into the sea.
The Mekong River began to cut fast and deep into the Tibetan Plateau ~17 million years ago. Exceptionally warm climate and intense summer monsoon rains helped sink the river into the soil; a river carved by erosion rather than tectonic force.
Before reaching the South China Sea, the Mekong River disintegrates into a network of distributaries, forming a biologically diverse ecosystem. The Mekong Delta is a swampy forest, dominated in the south by flat flood plains.
Hominids settled in the Mekong Delta ~2 million years ago, readily fed by its richness. At the onset of the 20th century, the soil of the Mekong Delta was still fecund, and its waterways full of fish. The situation has dramatically changed.
The flow of the Mekong has been greatly diminished by a myriad of dams built along its course. Reaping hydroelectricity has hard hit the natural life which was once so abundant. The dams also strip the Mekong of essential sediment which naturally fertilizes vegetation downstream.
Weather patterns are shifting worldwide. El Niño’s effects grow stronger as Earth warms: the Americas are drenched while southern Asia becomes parched. El Niño is a periodic climate pattern in the tropical Pacific Ocean which causes global shifts in storms, rainfall, and temperature.
Drought now plagues southeast Asia. Crop yields of all kinds are down, including rice and coffee. Some of this owes to the Delta region becoming saltier: a condition abetted by the plethora of wells dug for fresh water. As the Delta dries, brine from the sea pushes up the water channels, spreading into surrounding land.
Pumping water from wells also causes subsidence. In 2015, the Delta was less than 2 meters above sea level. By 2050 it will be less than 1.
Government pressure to maintain agricultural production has spelled greater application of fertilizers and pesticides, which spread pollution, restrict sediment flow, and accelerate soil degradation.
The efforts at intensive production will eventually fail in self-organized criticality. A once prodigiously fertile land will be abandoned as its waters no longer support the people that poisoned it. The depopulation will be a die-off.
Despite the gloom and doom espoused by scientists and even a few political leaders, there has been no urgency in addressing climate change. International agreements have been nothing more than gauzy ambitions.
Part of the reason for inaction is that in many places, warmer weather has been welcomed. Storms are spotty enough to not have caused sufficient consternation for alarmed determination to set in. It is as if a long fuse to a bomb has been lit, but instead of inciting dread, folks are enjoying the sparkler effect as the wick burns down.
The warnings about global warming have been extremely clear for a long time. We are facing a global climate crisis. It is deepening. We are entering a period of consequences. ~ Al Gore in 2005
Earth is habitable for animals because of its orbital proximity to the Sun, and because of the natural clemency that the atmosphere and oceans confer on surface temperature. Water vapor and a mixture of gases keep the planet at least 33 ºC warmer than it would be without its blanket of air.
Earth’s atmosphere reflects 30% of the Sun’s rays that it receives and absorbs another 30%. The remaining 40% drenches the surface in warmth and light.
Warmed surfaces send most of the heat back into the atmosphere, chiefly via infrared radiation, ascendant warm air, and evaporated water.
Greenhouse gases, such as carbon dioxide, absorb and emit heat via infrared radiation. When such radiation from Earth’s surface hits a molecule in the atmosphere, the molecule absorbs the heat energy and emits it later.
Toasted gas molecules fire infrared energy in a random direction. Sometimes the emitted heat heads into space. Other times the warmth spreads toward the surface, creating a greenhouse effect.
The atmospheric concentration of greenhouse gases embodies a balance between emission sources and sinks which absorb heat. Oceans, forests, and soils serve as Earth’s carbon sinks. But it is the fossil fuel deposits so prized by man that are the greatest global sink of carbon. Our self-destruction largely owes to burning the carbon which kept the planet habitable because it was deposited.
The legacy of our fossil fuel burning today could last for tens of thousands of years, if not hundreds of thousands of years to come. ~ American oceanographer Richard Zeebe
◊ ◊ ◊
Air in the human era has been nominally 78.09% nitrogen (N2), 20.95% oxygen (O2), 0.93% argon (Ar), and 0.04% carbon dioxide (CO2), with trace amounts of other gases.
Nitrogen, oxygen, and argon are not greenhouse gases, as they form monatomic molecules which are not rattled when jostled. Being energetically unaffected by infrared radiation means they generate no greenhouse effect.
Water vapor (H2O) continues to have the greatest greenhouse effect. The water cycle has played an enormous role in making and keeping Earth habitable.
There is a positive feedback loop among greenhouse gases and water vapor that generates a warming gyre. By trapping extra heat, greenhouse gases affect the amount of water vapor in the air. Heating the air by adding CO2 means the air takes up more water vapor, which further warms the atmosphere. Thus, greenhouse gases engender a multiplier to their warming effect.
In this century, as more attention has been paid, assessments of greenhouse gas emissions have regularly been revised upwards. The emissive impact of human activity has been underestimated, which means the situation is direr than commonly reported.
CO2 is the principal gaseous determinant of Earth’s climate state. It essentially acts as the radiative “control knob” that sets global temperature. Contributing 63% toward aeriform global warming, carbon dioxide is by far the gas with the greatest greenhouse kick.
The rising level of atmospheric CO2 is a direct product of deforestation and life under industrialization, principally through the burning of fossil fuels.
Clearing forests delivers a double shot of carbon dioxide. CO2 is released by the felling or burning. Moreover, the loss of vegetation removes a natural absorber (sink) of CO2.
The atmospheric carbon dioxide level in 1750, before industrialization, was 280 parts per million (ppm). By the end of World War 2 it had hit 300. The human world was emitting 6 billion tonnes of CO2 into the atmosphere annually.
The global level of atmospheric CO2 went over 400 ppm in 2013. The last time carbon dioxide levels were that high was 3 million years ago, when sea levels were 20 meters higher. In May 2019, global CO2 was at 415 ppm.
In 2017, humanity pumped 41 billion tonnes of CO2 into the air: over 600% more than the mid-20th century. And human injection of CO2 into the atmosphere continues to rise. Carbon emissions rose 2% in 2018 from the previous year.
The current rate of CO2 increase is over 100 times faster than in at least the last billion years, if ever in the planet’s history; a rate that will continue as long as worldwide fossil fuel consumption continues at its current level but is more likely to increase.
Once installed, CO2 persists in the air for a century. Humanity has already locked in accelerating global warming for the rest of its existence.
Plants to the Rescue
Plants have been giving us a chance to mend our ways. Global warming and rising CO2 have been met with a wash of greenery all over the world.
While plants appreciate the present climate change, vegetation will not be our salvation. Changing patterns of rainfall mean that lush times are limited, and the hotting up will prove too much for all concerned. Boreal and tropical forests alike will succumb to the swelter. Meanwhile, thawing tundra spells massive methane release, as soil that has locked greenhouse gases away for millions of years yields to the heat.
The verdant window of opportunity is already shut. Plants are less of a global force against warming than they were at the turn of the 21st century. Already, tropical forests contribute more carbon dioxide to the atmosphere than they remove, thanks to deforestation and a decline in diversity among the remaining trees.
Atmospheric carbon correlates with moisture. During dry years, natural ecosystems remove 30% less carbon from the air than during a normal year.
To much of life’s detriment, Earth becoming more arid accelerates warming in a positive feedback loop. Vegetative suffering from drought related to atmospheric CO2 has not been factored into climate models, which is another way that extant projections underestimate future global warming.
Our national flower is the concrete cloverleaf. ~ American historian and sociologist Lewis Mumford
By weight, concrete is the 2nd-most-consumed substance on Earth, behind water. On average, every person on the planet chews through 2.7 tonnes of cement each year. 4.3 billion tonnes were consumed worldwide in 2014. Concrete is used to build roads, runways, sidewalks, bridges, buildings, and dams.
China consumes over half the cement made, and produces 60% of it, followed at a distance by India and the US.
Concrete-like materials were used by Levant Arabs in 6500 bce. By 700 bce they had discovered the advantages of mortar made of hydraulic lime, whereupon kilns were built to construct rubble-wall houses with concrete floors.
The Arabs also constructed underground waterproof cisterns, the locations of which they kept to themselves. This secret water supply let them thrive in the deserts where they lived (after having deforested the land millennia prior).
The first people to employ concrete on a large scale were the ancient Romans, who were eager employers of the hard stuff. The Roman Colosseum was made of concrete, as were the other grand buildings that pronounced the prowess of the Empire.
After the Roman Empire collapsed, concrete was largely forgotten until its redevelopment in England during the mid-18th century, whereupon concrete was used to build the modern urban jungle.
The primary ingredient in concrete is cement, which is made today by heating limestone and clay until it fuses into a material called clinker, which is then combined with gypsum: the sulfate stuff from which plaster and blackboard chalk are made. The kilns used to create clinker are commonly fueled to extremely high temperatures by coal.
The concrete that the Romans made is superior to the modern variety. Chemical reactions on modern concrete after it hardens can only be damaging. In contrast, Roman concrete becomes stronger with time.
The Roman cement recipe was a mix of volcanic rubble and ash, lime (calcium oxide), and seawater. That combination naturally generates heat, turning the conglomeration into concrete. Whereas seawater degrades modern concrete, it strengthens Roman concrete by creating new minerals which fill any cracks and reinforce the material’s structure.
Open-pit mining for limestone is environmentally destructive. Both the intense heating and the chemical reactions involved in cement manufacture produce prodigious amounts of carbon dioxide. Cement production contributes 5% of all fossil-fuel-based CO2 emissions worldwide.
The great weight of cement makes it tough to transport; so markets are localized. But the local nature of cement has not stopped the capitalist urge for control. Just 5 behemoth firms dominate the global market.
Other significant greenhouse gases generated by human activity include methane (CH4) nitrous oxide (N2O), ozone (O3), and chlorofluorocarbons (CFCs).
Methane is much more complicated once it gets into the atmosphere than carbon dioxide is. That’s because it reacts with a lot of different important chemicals. ~ American climatologist Drew Shindell
Via its promiscuous reactivity, methane (CH4) is 84 times more potent as a greenhouse gas than carbon dioxide (CO2); but there is over 200 times more CO2 in the atmosphere than CH4.
Methane has a relatively short lifetime in the atmosphere: 12 ±3 years. Nonetheless, methane musters 25% of the global greenhouse effect.
Short-lived greenhouse gases contribute to sea-level rise through thermal expansion over much longer time scales than their atmospheric lifetimes. Amazingly, a gas with a 10-year lifetime can actually cause enduring sea-level changes.
As heat goes into the ocean, it produces continued thermal expansion. Then the heat is transferred back to the atmosphere and emitted back into space to cool off. That’s a very slow process of hundreds of years. ~ Canadian geologist Kirsten Zickfield & American atmospheric chemist Susan Solomon
Methane is naturally produced via geochemical concoction belowground, organic matter decomposition, and animal digestion. The biological contribution comes courtesy of methanogens: archaeal microbes that consume carbon dioxide and exude methane waste.
Methanogens make the marsh gas in wetlands, the bellow in cattle belches, and the flair of flatulence. Termites are little methane engines, thanks to their digestive archaea.
Though many methanogens live in the mud, soil is a net methane sink, which is precisely why the ancient dirt that comprises fossil fuels is so laden with methane.
The methanogens in the marshlands are excited about global warming. The hotter it gets, the happier they are.
The higher the temperature, the more efficient they are at producing methane. ~ English climatologist Paul Palmer
Wetland methane production is illustrative of feedback loops inherent in the climate system.
Global warming is causing these wetlands to produce more methane. And the methane is causing more global warming. ~ Paul Palmer
Methane also comes from human endeavors. Sources include mining, drilling, consumption of fossil fuels, garbage dumps, livestock, and rice paddies. At least 2/3rds of emitted methane is man-made. Every oil and gas well copiously leaks methane and other greenhouse gases.
Natural gas has been touted as a relatively “clean” fossil fuel. It is anything but: natural gas is mostly methane, and the American natural gas industry has been careless about leaks. Over $4 billion in natural gas is leaked into American air annually. Much of it emanates from manufacturing ammonia fertilizer, which uses natural gas as a feedstock and fuel.
Natural gas losses are a waste of a limited natural resource, increase global levels of surface ozone pollution, and significantly erode the potential climate benefits of natural gas use. ~ American chemist Ramón Alvarez et al
The climate impacts of burning coal in a modern plant versus natural gas in a modern plant are similar as a result of the supply-chain methane emissions. ~ American environmentalist Fred Krupp
Man-made methane emissions are likely to be at least double the estimates used in climate models prior to 2018. Further, ethane and propane emissions, which are also potent greenhouse gases, are probably 3 times as extensive as figured. Ethane and propane are byproducts of natural gas and petroleum drilling and refining.
US oil and gas drilling have been the primary source for the rise of atmospheric ethane in recent years, reversing a trend. About 60% of the drop we saw in ethane levels over the past 40 years has already been made up in the past 5 years. If this continues, we are on track to the maximum ethane levels in the 1970s. ~ German atmospheric chemist Detlev Helmig in 2016
People eat more meat when they can afford to. Global animal flesh consumption went from 40 million tonnes in 1950 to 270 million tonnes in 2010. If the trend holds, the eating of meat doubles by 2050.
Livestock digestive tracts are well stocked with methanogens. The ruminants raised and consumed by humans have been responsible for 18% of the global warming since the machine age began: a greater contribution than all the traveling to-and-fro in fossil-fueled vehicles such as cars and planes.
One side effect of atmospheric methane is the production of ozone, which, near the ground, is another potent greenhouse gas. Whatever its surface-level malfeasance, in the stratosphere, ozone is a protector of inhabitants below. But, before heading into the ozone, a quick snort of laughing gas (nitrous oxide).
Nitrous oxide is another potent greenhouse gas generated by agriculture, industrial activity, and waste. N2O has 300 times the greenhouse power of CO2 and lingers in the air for 120 years. In reaction with oxygen, N2O gives rise to nitric oxide (NO), which in turn reacts with ozone to break it down. Though there is scant nitrous oxide in the air, its contribution to global warming is considerable: 10%.
Over 1/3rd of N2O emissions are man-made. The countries with the greatest nitrous oxide output are China, Brazil, and the United States.
Oxygen in the stratosphere (10–50 km up) encounters ionizing radiation. The O2 breaks up, recouping itself into a molecular mass of O3: ozone.
The stratospheric ozone layer (20–40 km) has a mere 10 parts per million (ppm) of O3, compared to 0.3 ppm in the air below, but that margin in the ozonosphere is crucial to rendering the planet habitable.
The ozone layer absorbs ~98% of the Sun’s medium-frequency ultraviolet light (200–315 nm wavelength); UV radiation which otherwise would be hazardous to life on the surface, such as engendering cancer in humans.
A thinner ozonosphere facilitates global warming by letting in more sunlight, but ozone layer depletion does not affect the absorption of heat in the atmosphere.
The ozonosphere does have an indirect effect on global climate. A hole in Antarctic ozone layer caused by man-made aerosol pollution changed the way that waters mixed in the Southern Ocean.
Formation of the Antarctic ozone hole has caused large-scale coherent changes in the ventilation of the southern oceans. Southern oceans play an important role in the uptake of heat and carbon dioxide, so any changes in Southern Ocean circulation have the potential to change the global climate. ~ American climatologist Darryn Waugh
The ozone layer is depleted by free-radical catalysts, which break reactive O3 (ozone) back into the benign O2 we eagerly breathe. Chlorofluorocarbons (CFCs) are a class of such catalysts, as is nitrous oxide. CFCs contain only carbon, chlorine, and fluorine in various configurations. CFCs are potent greenhouse gases.
From the late 19th century into the early 1980s, CFCs were used extensively in aerosols and as refrigerants. CFCs were adopted for many industrial processes because they seemed inert: they did not burn, did not react with other substances, nor were they particularly poisonous. Environmentally, the relative stability of CFCs is a substantial hazard: their slow breakdown in the atmosphere produces chlorine free radicals which decimate the ozonosphere.
The lingering presence of CFCs in the atmosphere and their power to extinguish ozone was belatedly discovered in the mid-1970s. They were then quickly regulated, though some CFCs remain in use, as chemists have yet been able to concoct acceptable substitutes. That we refuse to inconvenience ourselves to save ourselves is exemplary of the collective folly which ensures self-extinction.
Because CFCs remain in the stratosphere for up to 100 years, they will deplete ozone long after industrial production of the chemicals ceases. ~ American environmental scientist Bruce Johansen
Thomas Midgley Jr.
When I’m gone, I have no regrets to offer. ~ Thomas Midgely Jr. in 1944
By the time he died, American mechanical and chemical engineer Thomas Midgley Jr. (1889–1944) was hailed as one of the great inventors of the 20th century. Certainly, his legacy was lasting.
Midgley began working at General Motors in 1916. In 1921, Midgley discovered how to prevent “knocking” in gasoline engines: add a bit of lead. GM deceptively advertised the additive as “Ethyl,” avoiding any mention of the well-known toxicant. In 1923, Midgley took a long vacation, hoping to cure himself of lead poisoning.
The development of lead poisoning will come on so insidiously that leaded gasoline will be in nearly universal use before the public and the government awaken to the situation. ~ American physiologist Yandell Henderson in 1924
Leaded gasoline was adopted worldwide, despite scientific outcry. Only in the early 2000s was the deadly additive phased out in most industrialized countries.
In the late 1920s, GM had Midgley working on a way to improve the refrigerants used in refrigerators and air conditioners. The currently used chemicals were toxic, flammable, or explosive.
Midgley settled on a chlorofluorocarbon (CFC), which was trademarked “Freon.” (Belgian chemist Frédéric Swarts pioneered the synthesis of CFCs in the 1890s.) CFCs went on, in various concoctions, to keep devices and people cool worldwide.
Highly stable, non-inflammable and altogether without harmful effects on man or animals. ~ American mechanical engineer Charles Kettering, who worked with Midgley at GM in developing ethyl and CFCs
In 1974, American chemist Sherwood Rowland and Mexican chemist Mario Molina published an article suggesting that CFCs were eating huge holes in the atmospheric ozone layer, which helps keep the planet cool. CFCs were ostensibly banned worldwide by 2110, but their use continues, albeit at a much lower rate than in the mid-1990s, when many countries belatedly decided something should be done.
Midgley contracted polio at 51, rendering him severely disabled. He devised an elaborate motorized system of cables and pulleys to help lift him from his bed. In 1944, Midgley died of strangulation, having become ensnared in his own contraption.
Global warming is the most telling cause of climate change. Another facet is global dimming: reducing the Sun’s radiation from reaching Earth’s surface because of a blanket of atmospheric particulates. These pollutants are both natural – from volcanic eruptions and forest fires – and via man-made aerosols.
The cooling effect of global dimming has been overwhelmed by greenhouse gas release. Even worse, global dimming has an adverse effect on the lives of plants and other organisms that thrive on sunlight.
Global dimming cannot be considered a positive aspect of climatic dynamics, such as a counter to global warming. The dimming is instead another disruption in Earth’s climate gyre, and an attack on ecosystem survival worldwide.
Global warming is ocean warming. ~ American oceanographer Gregory Johnson
The release of greenhouse gases into the air and surface warming is only the most obvious aspect of the global warming gyre. The oceans soak up atmospheric heat: absorbing over 90% of the heat energy added to the world’s climate system. The oceans are the world’s largest natural carbon sink.
Observed estimates of global ocean warming since 1970 were low. ~ American oceanographer Paul Durak et al in 2014
In 2018, researchers found that ocean temperatures were rising 40% faster than estimated just 5 years earlier.
We thought that we got away with not a lot of warming in both the ocean and the atmosphere for the CO2 emitted. We were wrong. The planet warmed more than we thought. It was hidden from us just because we didn’t sample it right. But it was there, in the ocean already. ~ American geoscientist Laure Resplandy in 2018
The thermal toll on the oceans is accelerating: Earth’s oceans absorbed heat in 2017 at twice the rate as 2000. Half of ocean heat uptake since 1865 has taken place since 1997.
Just as heatwaves induce wildfires on land, marine heatwaves are increasing in frequency and severity, destroying coral reefs, kelp forests, seagrass meadows, and other oceanic ecosystems in just weeks or months. 1987–2016, marine heatwaves jumped over 50% compared to 1925–1954.
Without humans, the natural carbon cycle would be balanced. Instead, oceans manage to absorb only 1/3rd of man-made CO2 emissions. Too much man, too little ocean.
We’re only just now discovering how important ocean warming is. ~ American oceanographer Joellen Russell in 2018
Temperature is the most important environmental factor determining the composition of plankton communities. ~ English marine biologist Chris Bowler
Phytoplankton (aka microalgae) are the autotrophic members of the plankton community: those able to synthesize their own energy via photosynthesis. Almost all microalgae are microscopic, but they add up to be a huge factor in the oceans being livable. Marine phytoplankton account for nearly half of global primary productivity, thereby serving as the fundamental food source for heterotrophs in the food web. Phytoplankton also play essential roles in the global cycles of carbon, nitrogen, phosphorus, and other elements.
Phytoplankton have not been happy with the warmer water: migrating poleward for cool relief. Many struggle to adapt as quickly as the ocean is changing. A steady decline in phytoplankton numbers in the early 20th century accelerated mid-century. 1950–2010, global microalgae populations dropped 40%. The hotting up is especially affecting tropical plankton, decreasing their diversity as species go extinct.
A decrease in diversity is likely to have a strong impact on tropical ecosystems, because biodiversity loss is a major cause of ecosystem change. ~ marine ecologist Mridul Thomas
Sea animals are more vulnerable to warming than are land ones. ~ Australian ecologist Anthony Richardson & South African ecologist David Schoeman
The brisk ocean warming is killing marine life at a rapid clip. Worldwide, populations of everything from phytoplankton to coral to whales are being decimated because of ocean heat and acidification.
There’s an intimate relationship between the amount of carbon stored in the ocean and what the climate is doing. ~ American Earth scientist Jesse Farmer
25% of the carbon dioxide pumped into the atmosphere ends up in the ocean. Through a series of chemical reactions, oceans acidify as they absorb CO2.
Since industrialization, the world’s oceans have become 30% more acidic. Marine pH continues its freefall. The oceans are now more acidic than they have been for over 2 million years. Many organisms cannot stand the rising astringency. Among other effects, fish lose their sense of smell, greatly reducing their ability to survive.
Climate warming has been wreaking havoc with marine ecosystems. ~ American oceanographer Charles Greene
Besides heat and acidity, some of the kill-off owes to the seas losing oxygen. Most marine life needs oxygen to survive. Even slight decreases in oxygen content can have severe consequences on ocean ecosystems, especially when combined with other detrimental dynamics.
Earth’s oceans lost over 2% of their oxygen 1960–2015. Anoxia more than quadrupled over that period. Oceanic life is being starved of oxygen; a trend that is accelerating. Coral reefs in anoxic zones quickly die off.
Oxygen concentrations in both the open ocean and coastal waters have been declining since at least the middle of the 20th century. This oxygen loss is one the most important changes occurring in the ocean and may result in ecosystem collapses. ~ American marine biologist Denise Breitburg et al
The Arabian Sea is the largest and thickest dead zone in the world. The area of dead zone is vast and growing. The ocean is suffocating. ~ English marine biogeochemist Bastien Queste
For days, a female lobster squirts urine into the den of her desired mate. Beguiled by the scent, he lets her move in. Foreplay lasts for days: stroking each other with antennae and feet, which are covered with scent receptors.
Once she’s convinced that he’ll protect her, a female disrobes: slowly shedding her hard shell and the pouch where she had banked sperm from her last mate. Molting leaves her vulnerable, so he stands guard for the half hour it takes for her new soft shell to harden. Then, supported by his hind claws, he suspends himself above her, and lifts her to face him, cradling her in his legs.
Her new shell has a new sperm pouch, into which he thrusts a packet of sperm using his gonopods: the specialized appendages that male lobsters use to transfer sperm. The deed is done.
After she departs, he will welcome another female. Meanwhile, the departed female will use her sperm packet to fertilize thousands of eggs, which she will carry under her tail for a year until the larvae hatch.
Lobsters only mate when the water’s cold. In warm water, lobsters instead put their energy into growing. With constantly warm water, lobsters simply stop mating.
If it’s steadily too warm, they just won’t produce. No eggs. No sperm. No lobsters. ~ American marine biologist Diane Cowen
Deglaciation & Rising Sea Level
It takes sea-level rise a very long time to react — on the order of centuries. It’s like heating a pot of water on the stove: it doesn’t boil for quite a while after the heat is turned on, but then it will continue to boil as long as the heat persists. Once carbon is in the atmosphere, it will stay there for tens or hundreds of thousands of years, and the warming, as well as the higher seas, will remain. ~ American geoscientist Peter Clark
Even if we were to freeze greenhouse gases at current levels, the sea would actually continue to warm for centuries and millennia, and as they continue to warm and expand the sea levels will continue to rise. ~ Gregory Johnson
Since glaciers and ice caps are masses of land-based frozen water, their melting and runoff into the oceans causes sea levels to rise. In contrast, because sea ice formed in the ocean and floats there, its loss would be relatively insignificant to sea-level rise.
Even without deglaciation, sea levels would rise simply from the waters becoming warmer. Matter, including H2O, expands when heated. Warming invokes thermal expansion.
The Last Glacial Maximum was the last period of severe glaciation. Ice sheets reached their maximum 26.5 thousand years ago (tya). Deglaciation commenced in the northern hemisphere 19 tya. Antarctica started shedding ice 14.5 tya, provoking an abrupt rise in sea levels. At the time, vast ice sheets covered much of North America, northern Europe, and Asia.
Ice mass loss from the most vulnerable ice, sufficient to raise sea level several meters, is better approximated as exponential than by a more linear response. ~ James Hansen et al
Over the past century, sea level rose at an average rate of 1.5 mm, increasing to 3.2 mm a year 1990–2010. The rise is accelerating, as the large ice masses of the world melt. Artic ice and the glaciers of the Himalayas will be gone well before the end of the century; perhaps even Antarctica’s ice too, as the rate of ice decline there since 2014 has been precipitous.
In the 1st decade of the 21st century, changes in the global water cycle more than offset the terrestrial losses from human extraction. The land has been acting as a sponge: soaking up an extra 2.9 trillion tonnes of water in soils, lakes, and underground aquifers. This has temporarily slowed sea-level rise by 20%.
Climate-driven land water storage uptake is of opposite sign and of magnitude comparable with ice losses from glaciers and ice sheets and nearly twice as large as mass losses from direct human-driven changes in land water storage. ~ American hydrologist J.T. Reager et al
How long the land has been soaking up extra water is not known. But one thing is certain: once the crust is saturated, sea-level rise will quicken.
Sea-level rise is going to continue to accelerate if there’s further warming, which inevitably there will be. ~ German ocean physicist Stefan Rahmstorf
◊ ◊ ◊
2016 estimates foretold global sea-level rise close to 3 meters by 2100: more than double the estimated rise in 2006, and 25% more than in 2012. Revisions to sea-level rise in the geological near-term keep going up. In 2017, the prediction was over 3 meters: up nearly 20% from just a year earlier.
Changes in ocean currents will affect the way that seawater is distributed throughout the world. Further, melting glaciers are likely to affect Earth’s gravitational field and even its rotation, which will also alter current flows.
Sea-level rise will be more pronounced in certain areas, such as on the east coast of North America.
Continued warming assures sea-level rise for centuries to come.
Sea level rise has the potential to affect millions of people living in low-lying coastal regions, particularly the inhabitants of megacities on coasts around the world, and those living on deltas of major rivers and small island nations. ~ Australian climatologist John Church in 2004
Entire populations of cities will eventually have to move. ~ Peter Clark
Measures to deal with sea-level rise take a lot of time and sustained political will. Britain erected a storm surge barrier on the Thames River after a catastrophic 1953 storm in which over 2,000 people perished; but it took almost 30 to do so, and that was fast compared to similar construction projects.
American Toxic Sites
There are over 2,500 toxic chemical sites in flood-prone areas of the US. Every state has at least 1.
Federal, state, and local governments have no regulations for safe siting. Floods in recent years have repeatedly unleashed lethal regret.
Governments don’t even bother to track toxic spills from floods when they occur. (A 2015 US presidential executive order requiring assessment of flooding potential for federally funded infrastructure was rescinded by President Trump in 2017.)
It was like the biblical flood, well off the charts. The lesson learned is that every now and then there will be something that’s more than we planned for. ~ American corporate spokesman Mike Williams, about the toxic spill from an agrichemical plant in Houston, Texas in 2017
At the Poles
“The Arctic is changing incredibly rapidly; much more rapidly than the rest of the world.” ~ American climatologist Tim Garrett in 2018
The polar regions are especially prone to global warming. Due to geothermal feedback loops, the Arctic has been hotting up at twice the rate of the global average over the past century. In early 2019, Arctic air temperatures were 40 °C above the 20th-century historical average.
“What happens in the Arctic doesn’t stay in the Arctic: it affects the rest of the planet. The Arctic has huge influence on the world at large.” ~ American oceanographer Timothy Gallaudet
“By upsetting the energy balance of the planet we are changing the temperature gradient between the equator and the pole. This in turn sets in motion major reorganisations of the flow patterns of the atmosphere and ocean.” ~ English climatologist Chris Rapley
Besides heat, the Artic has been especially hard hit by ocean acidification.
“The Arctic Ocean is the first ocean where we see such a rapid and large-scale increase in acidification, at least twice as fast as that observed in the Pacific or Atlantic oceans.” ~ Chinese marine chemist Wei-Jun Cai in 2017
Changes in the Arctic atmosphere affect the lower latitudes via the polar vortex and jet streams. The polar vortex is the gyre of low pressure and cold air at both of the planet’s poles.
A jet stream is an atmospheric river that nominally flows from west to east in accordance with Earth’s rotation, and with wavy latitudinal shifts according to climatic conditions. There are polar (~50º–60º latitude) and subtropical (30º) jet streams.
As the Arctic warms, the polar vortex weakens and the polar jet stream becomes wavier, bringing warmth to the Arctic and cold air to lower latitudes.
“The Arctic is undergoing dramatic changes linked to climate change, including a rapid decline in sea ice. As sea ice shrinks, it disrupts the natural functioning of the ecosystem.” ~ American marine biologist Amber Hardison
At the current rate of warming, the Arctic will ice-free by 2045; probably sooner. The Arctic Ocean has not been iceless in the summer for over 125,000 years.
Polar bears are headed to extinction, as are penguins and many other animals dependent upon a habitat with sea ice.
“No sea ice means no seals. And no seals means no polar bears.” ~ Canadian zoologist Andrew Derocher
◊ ◊ ◊
Changes at the south pole are also occurring, but at a more glacial pace. Southern Ocean currents which surround Antarctica are helping keep the continent cool, as upwelling deep, cold water fends off warming.
The oceans are acting to enhance warming in the Arctic while damping warming around Antarctica. ~ American oceanographer Kyle Armour
The cool at the south pole won’t last. Already sea ice shelves are cleaving around Antarctica and floating out into the ocean. The melt rate of Antarctica’s ice sheet tripled in the decade of 2008–2017. Antarctic ice loss in 2018 was 5 times faster than 20 years earlier.
When the ice finally starts seriously melting at the south pole, it is likely to trigger catastrophic changes. There are 138 sleeping volcanoes underneath Antarctica, some of which are likely to wake up when the ice cover lessens. Then the south pole will become a blow torch to global warming.
“Without ice sheets on top of them, there is a release of pressure on the regions’ volcanoes and they become more active.” ~ English geophysicist Robert Bingham
As the Arctic rapidly warms, permafrost – perennially frozen soil – is thawing fast. As ground temperature climbs above freezing, microbes break down organic matter in soil, releasing greenhouse gases that accelerate global warming. Permafrost soils hold twice as much carbon as the atmosphere: 1,600 billion tonnes.
Current climate models assume that permafrost gradually thaws from the surface downwards. Deeper layers become exposed only over decades or even centuries.
The models ignore that frozen soil doesn’t just lock up carbon – permafrost physically holds the landscape together. Across the polar regions, including boreal forests, permafrost is collapsing suddenly from ice melt. Instead of a few centimeters of soil thawing each year, several meters of soil destabilize within days or weeks. The land sinks and becomes inundated with swelling wetlands and lakes. Forests flood, killing vast stands of trees.
Worse, the most unstable regions are the most carbon rich. Over 1 million square kilometers of Alaska, Canada, and Siberia are larded with Yedoma: thick permafrost deposits from the last ice age. Yedoma is often 90% ice, making it extremely vulnerable to warming. Moreover, Yedoma collectively contains 130 billion tonnes of organic carbon: equivalent to over a decade of the greenhouse gases that human emit in their industrial endeavors.
The warming impact from thawing permafrost is likely to be at least twice that expected from current models.
The World in Motion
Swiftly hotting up is rapidly transforming Earth in many ways. Shifts in the world’s oceans are inciting volcanic activity and tectonic plate movements.
A telltale indicator is that north magnetic pole is sliding from northern Canada to Siberia at an accelerating pace. Global warming is even affecting the rotation of the outer core of the planet.