IPCC admits the end of the world as we know it

The United Nations Intergovernmental Panel on Climate Change has just come out with its latest report on the Earth’s ecosystemic health, and even in its gussied up findings — what many are calling “hopium” these days — it is, if read carefully, a prediction of the end of civilization.

According to the U.N. report, the only way to avoid this disaster would require “rapid and far-reaching” changes in the capitalist system that is the substructure of civilization, East and West. What must be changed, it says, are energy systems, land use, urban design, transportation, and building design — at a minimum. Changed so they contribute no greenhouse gases to the atmosphere — and can you imagine a world where transportation, for example, doesn’t pollute the air and we get along without cars, airplanes and cargo ships?

Though “energy systems” looks like a mild phrase, it actually implies the end of coal, gas and oil in the near future, the very fuels upon which industrial capitalism is based. There is no way that so-called “renewable” sources (which of course are not renewable because solar panels, windmills and batteries have finite lives and must be replaced) could ever replace those carbon-based fuels.

No wonder that most scientists — and anybody else who knows how politics works — say that this sort of wholesale economic change will not come about. There’s not a political system of any stripe anywhere in the world that is prepared to, or even knows how to, transform a society out of our modern way of life. That’s why one scientist has said in response to the U.N. report that it is nothing more than an academic exercise in “what would happen if a frog had wings.”

A decade ago, the “father of global warming”—the first scientist to sound the alarm on climate change in the 1980s to the US Congress—announced that we were too late: the planet had already hit the danger zone.

In a landmark paper, James Hansen, then head of NASA’s Goddard Institute for Space Studies, along with seven other leading climate scientists, described how a global average temperature above 1°Celsius (C)—involving a level of carbon dioxide (CO2) in the atmosphere of around 450 parts per million (ppm)—would lead to “practically irreversible ice sheet and species loss.” But, they added, new data showed that even 1°C was too hot.

At the time the paper was issued in 2008, atmospheric concentrations of CO2 were around 385 ppm. This is “already in the dangerous zone,” explained Hansen and his colleagues, noting that most climate models excluded self-reinforcing amplifying feedbacks which would be triggered at this level—things like “ice sheet disintegration, vegetation migration, and GHG [greenhouse gas] release from soils, tundra, or ocean sediments.”

Such feedbacks constitute tipping points which, once triggered, can lead to irreversible or even runaway climate change processes.

According to Hansen and his co-authors, these feedbacks “may begin to come into play on time scales as short as centuries or less.” The only viable solution to guarantee a safe climate, they wrote, is to reduce the level of greenhouse gases to around 350 ppm, if not lower.

Today, we are well in breach of the 1°C upper limit. And we have breached this limit at a much lower level of atmospheric CO2 than Hansen thought would be necessary to warm this much—as of May 2018, the monthly average atmospheric CO2 had reached 410ppm (the August measurement puts it at 409ppm.) This is the highest level of CO2 the earth has seen in 800,000 years.

The IPCC says that this would just be the beginning: we are currently on track to hit 3-4°C by end of century, which would lead to a largely unlivable planet.

They STILL haven’t dropped the other shoe. The “Special Report on Global Warming of 1.5C” contains terrifying forecasts about what will happen when we reach an average global temperature 1.5 degrees C higher than the pre-industrial average. (We are now at +1C.) But it still shies away from talking about the feedbacks, the refugees and mass death.

The report is a bracing dose of realism in many ways. It effectively says we can’t afford to go anywhere near +2C. It talks bluntly about the need to end all fossil fuel use, reforest vast tracts of marginal land, and cut down on meat-eating. It even admits that we will probably have to resort to geoengineering — “solar radiation management,” in the jargon.

So far, so good. At least it’s being honest about the problem — but only up to a point. “Not in front of the children” is still the rule for governments when it comes to talking about the mass movements of refugees and the civil and international wars that will erupt when the warming cuts into the food supply. And they still don’t want to talk openly about the feedbacks.

The governments take climate change very seriously these days, but they worry that too much frankness about the cost in lives of going past 1.5C will create irresistible pressure on them to take radical action now. In the ensuing struggle between the scientists and the politicians, the executive summary always gets toned down.

What got removed from the summary this time was any mention of “significant population displacement concentrated in the tropics” at +2C (i.e. mass migrations away from stricken regions, smashing up against borders elsewhere that are slammed shut against the refugees, the real reason for Trump's wall).

Even worse, “tipping points” are barely mentioned in the report. These are the dreaded feedbacks — loss of Arctic sea ice, melting of the permafrost, carbon dioxide and methane release from the oceans — that would trigger unstoppable, runaway warming.

They are called “feedbacks” because they are self-reinforcing processes that are unleashed by the warming we have already caused, and which we cannot shut off even if we end all of our own emissions.

If you don’t go into the feedbacks, then you can’t talk about runaway warming, and going to 4, 5 or 6 degrees C higher average global temperature, and hundreds of millions or billions of deaths. And if you don’t acknowledge that, then you will not treat this as the emergency it really is.

Just two years ago, amid global fanfare, the Paris climate accords were signed — initiating what seemed, for a brief moment, like the beginning of a planet-saving movement. But almost immediately, the international goal it established of limiting global warming to two degrees Celsius began to seem, to many of the world’s most vulnerable, dramatically inadequate; the Marshall Islands’ representative gave it a blunter name, calling two degrees of warming “genocide.”

The alarming new report you may have read about this week from the UN’s Intergovernmental Panel on Climate Change — which examines just how much better 1.5 degrees of warming would be than 2 — echoes the charge. “Amplifies” may be the better term. Hundreds of millions of lives are at stake, the report declares, should the world warm more than 1.5 degrees Celsius.

Nearly all coral reefs would die out, wildfires and heat waves would sweep across the planet annually, and the interplay between drought and flooding and temperature would mean that the world’s food supply would become dramatically less secure. Avoiding that scale of suffering, the report says, requires such a thorough transformation of the world’s economy, agriculture, and culture that “there is no documented historical precedent.”

If you are alarmed by those sentences, you should be — they are horrifying. But it is, actually, worse than that — considerably worse. That is because the new report’s worst-case scenario is, actually, a best case. In fact, it is a beyond-best-case scenario. What has been called a genocidal level of warming is already our inevitable future. The question is how much worse than that it will get.

Barring the arrival of dramatic new carbon-sucking technologies, which are so far from scalability at present that they are best described as fantasies of industrial absolution, it will not be possible to keep warming below two degrees Celsius — the level the new report describes as a climate catastrophe. As a planet, we are coursing along a trajectory that brings us north of four degrees. The IPCC is right that two degrees marks a world of climate catastrophe.

But the real meaning of the report is not “climate change is much worse than you think,” because anyone who knows the state of the research will find nothing surprising in it. The real meaning is, “you now have permission to freak out.”

At two degrees, the melting of ice sheets will pass a tipping point of collapse, flooding dozens of the world’s major cities. Four hundred million more people will suffer from water scarcity, and even in the northern latitudes heat waves will kill thousands each summer. It will be worse in the planet’s equatorial band. In India, where many cities now numbering in the many millions would become unliveably hot, there would be 32 times as many extreme heat waves, each lasting five times as long and exposing, in total, 93 times more people. This is two degrees — practically speaking, our absolute best-case climate scenario.

At three degrees, southern Europe will be in permanent drought. The average drought in Central America would last 19 months and in the Caribbean 21 months. In northern Africa, the figure is 60 months — five years. The areas burned each year by wildfires would double in the Mediterranean and sextuple in the United States. Beyond the sea-level rise, which will already be swallowing cities from Miami Beach to Jakarta, damages just from river flooding will grow 30-fold in Bangladesh, 20-fold in India, and as much as 60-fold in the U.K. This is three degrees — better than we’d do if all the nations of the world honored their Paris commitments, which none of them are. Practically speaking, barring those dramatic tech deus ex machinas, this seems to me about as positive a realistic outcome as it is rational to expect.

Key dangers largely left out of the IPCC special report on 1.5C of warming are raising alarm among some scientists who fear we may have underestimated the impacts of humans on the Earth’s climate.

The IPCC report sets out the world’s current knowledge of the impacts of 1.5C of warming and clearly shows the dangers of breaching such a limit.

Tipping points merit only a few mentions in the IPCC report. Durwood Zaelke, founder of the Institute for Governance and Sustainable Development, said: “The IPCC report fails to focus on the weakest link in the climate chain: the self-reinforcing feedbacks which, if allowed to continue, will accelerate warming and risk cascading climate tipping points and runaway warming.”






Thousands of Methane Filled Pingos Expected to Blow

The otherwise flat sea floor between the island archipelago of Svalbard and Finnmark, Norway’s northernmost county, is pocked by massive craters.

Now, scientists at the Centre for Arctic Gas Hydrates, Environment and Climate (CAGE) at UiT - The Arctic University of Norway, have collected new geophysical data on the craters in the area.

But instead of finding just a few craters, researchers found hundreds of them. They range in size from 300 to 1000 metres in diameter. And they have been blown out of solid bedrock.

The craters are what remain after a methane gas explosion. Or more correctly: gas blow-outs.

The blow-outs may have occurred over a couple of days.

But these blow-outs must have involved enormous forces at the bottom of the Barents Sea, since the holes have been blasted out of solid bedrock.

The researchers in Tromsø expect further blow-outs, as some gas chambers have not yet blown, and others are slowly building up pressure again.

Andreassen thinks there will be more large blow-outs in the ocean floor south of Svalbard, as the seabed becomes warmer and gas-hydrate reservoirs thaw.

Andreassen says there is probably even more methane gas locked in the seabed around Greenland and in the Arctic Ocean than is found in the Barents Sea.

That could lead to some extremely large craters.

Researchers have now examined satellite images of northern Siberian from a few years back and looked at the area where the explosions occurred. They found that the year before the huge crater appeared, there were large pingos in the same place.

Russian scientists have now mapped 7,000 gas-filled pingos that are poking through the thawing permafrost, visible in satellite images that illustrate how the pingos form and grow.


An adaptability limit to climate change due to heat stress

Despite the uncertainty in future climate-change impacts, it is often assumed that humans would be able to adapt to any possible warming. Here we argue that heat stress imposes a robust upper limit to such adaptation. Peak heat stress, quantified by the wet-bulb temperature TW, is surprisingly similar across diverse climates today. TW never exceeds 31 °C. Any exceedence of 35 °C for extended periods should induce hyperthermia in humans and other mammals, as dissipation of metabolic heat becomes impossible. While this never happens now, it would begin to occur with global-mean warming of about 7 °C, calling the habitability of some regions into question. With 11–12 °C warming, such regions would spread to encompass the majority of the human population as currently distributed. Eventual warmings of 12 °C are possible from fossil fuel burning. Heat stress also may help explain trends in the mammalian fossil record.


Arctic Ice Collapse in the Heart of Winter

(Today, on Sunday February 25, 2018 at 0900 UTC — temperatures rose to above freezing at the North Pole, 34 F. What would typically be a summer-time temperature for this furthest north location of our world happening during February. )

The persistent weather patterns necessary for such an event were already well in play. At the surface, warm air was continuously running northward just east of Greenland — born pole-ward by powerful storms and frontal systems. At the upper levels of the atmosphere, a huge plug of warm air was developing. One that invaded the stratospheric levels of the atmosphere by the week of February 4-11. This plug, in synergy with surface warming, tore apart the heart of cold at the roof of our world that we call the Polar Vortex.

(Daily mean temperatures for the entire region of the Arctic above the 80 degree north latitude line rocketed upward to new records over recent weeks. Most recent temperatures are comparable to those typically seen during late May.)

Over the past 72 hours, gale force warm, southerly winds gathered in the Atlantic, then blasted north.

At this point, we were starting to see some seriously outlandish temperatures in the higher latitude regions. Cape Morris Jesup, which is the furthest north location on Greenland, by Friday the 23rd experienced a 6 C or 43 F temperatures on the shores of what should be a frozen solid Arctic Ocean just 400 miles from the North Pole.

The average high temperature in Cape Morris Jesup is -20 degrees Fahrenheit during February — making Friday’s reading a whopping 63 degrees F warmer than average. For reference, a similar departure for Washington, DC would produce a 105 degree day in February.

But it wasn’t just Cape Morris Jesup that was experiencing July-like conditions for the Arctic during February. For the expanding front of that ridiculously warm winter air by Sunday had expanded into a plume stretching tens of thousands of square miles and including a vast zone of temperatures spiking from 45 to 54+ degrees F above normal.

It appears that this particular warming event — the highlight of an ongoing polar warming of the past few weeks — is without precedent in the Arctic during February.


Add to that, that the Arctic ice is breaking up months early and being transported out through both the Fram and Nares when it should be frozen fast, we are seeing an unprecedented collapse of the Arctic ice in the very heart of what should be winter.

Not to mention the Bering Strait where it is just disappearing.

Discussion at ASIF - End of the World

Semiletov and Shakhova were not 'hinting' at anything. They were telling you point blank.

The area of hotspots of methane are spreading, now encompassing a full 10% of the 2 million sq km of the ESAS. Which is 200,000 sq km.

Not only is the area of release spreading, the rate and volume of release is increasing, and they expect it to increase exponentially 3-5 orders of magnitude.

That there is no way to shut this off, short of sea level dropping and exposing the shelves to temperatures capable of refreezing the permafrost. We know that isn't going to happen.

That the methane will continue to release until there is no more to release, and that just 1% of the available methane will be enough to cause catastrophic climate change.

The interview with Semiletov and Shakhova was published 24 June 2017. their paper, http://www.nature.com/articles/ncomms15872 Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf, was published 22 June 2017.






Subsea permafrost on East Siberian Arctic Shelf in accelerated decline

Dr. Shakhova: As we showed in our articles, in the ESAS, in some places, subsea permafrost is reaching the thaw point. In other areas it could have reached this point already. And what can happen then? The most important consequence could be in terms of growing methane emissions… a linear trend becomes exponential.

This edge between it being linear and becoming exponential is very fine and lays between frozen and thawed states of subsea permafrost. This is what we call the turning point. To me, I cannot take the responsibility in saying there is a right point between the linear and exponential yet, but following the logic of our investigation and all the evidence that we accumulated so far, it makes me think that we are very near this point. And in this particular point, each year matters.

Gas in the areas of hotspots is releasing from the seabed deposits, in which free gas has accumulated for hundreds of thousands, or even for a million years. This is why the amount of this gas and its power in releasing (due to its high pressure) is tremendous.

Dr. Shakhova: The importance of hydrates involvement in methane emissions is overestimated. The hydrate is just one form of possible reservoirs, in which pre-formed methane could be preserved in the seabed if there are proper pressure/temperature conditions; it is just the layer of hydrates composes just few hundred of meters – this is a very small fraction compared to thousands of meters of underlying gas-charged sediments in the ESAS.

Dr. Semiletov added that the 5 billion tonnes of methane that is currently in the Earth’s atmosphere represents about one percent of the frozen methane hydrate store in the East Siberian Arctic Shelf. He finishes emphasising  “…but we believe the hydrate pool is only a tiny fraction of the total.”

Dr. Shakhova: The second point is that the hydrates are not all of the gaseous pool that is preserved in this huge reservoir. This huge area is 2 million square kilometres. The depth of this sedimentary drape is a few kilometres, up to 20 kilometres at places. Generally speaking, it makes no difference if gas releases from decaying hydrates or from other free-gas deposits, because in the latter, gas also has accumulated for a long time without changing the volume of the reservoir; for that reason, gas became over pressurised too.

Unlike hydrates, this gas is preserved free; it is a pre-formed gas, ready to go. Over pressured, accumulated, looking for the pathway to go upwards.

In our observations, we have accumulated the evidence that this gas front is propagating in the sediments. To me as a scientist, these points are enough to be convinced that methane release in the ESAS is related to disintegration of subsea permafrost and associated destabilisation of seabed deposits whether it is hydrates or free gas accumulations.

There is no mechanism to stop permafrost disintegration in the ESAS besides shelf exposure above the sea level that would serve to freeze the gas migration paths so that they integrate with the permafrost. Before that, the amount of methane that is releasing will increase while the supply lasts.

As gas within the sedimentary basins of the ESAS have been accumulating for a million years with no way to be released earlier, the supply for currently occurring emissions is tremendous. Because the shelf area is very shallow (mean depth is less than 50 metres), a fraction of these emissions will reach the atmosphere. The problem is that this fraction would be enough to alter the climate on our planet drastically.


Health effects of increase in concentration of carbon dioxide in the atmosphere

The lowest value at which the atmospheric concentration of carbon dioxide could be stabilized by reduction of additions made by human activity (fossil fuel-burning, etc.) is estimated as 550 ppm. To achieve this, severe limitations are required on the latter activities. The most often quoted desirable/attainable stable concentration is 750 ppm. This concentration level is not related in any way to health considerations and is above the estimated dangerous level of 426 ppm. The value is also above the 600 ppm level, which results in the ‘stuffy room’ conditions described above. At the very least, 600 ppm of carbon dioxide in the atmosphere will be unpleasant and there will be no readily available means of reversing the changes giving rise to the above symptoms. Such a situation is unlikely to be tolerable for a lifetime by humans (and other mammals with the possible exception of seals) without deterioration in general health along with serious curtailing of physical activity presently taken as normal.
It is likely that when the concentration of carbon dioxide in the atmosphere reaches 426 ppm in less than two generations from the present date(2005), the health of at least some sections of the world population will deteriorate, including those of the developed nations. It is also obvious that if the extremes of conditions described above come to pass, then the biosphere and humankind are seriously threatened.


The effects of elevated carbon dioxide on our health

We know that four out of five mass extinction periods can be linked to sudden rises in atmospheric carbon dioxide concentrations. In the ocean, acidification is thought to be a main factor in this, while temperature increases lead to mass extinctions both on land and in the ocean. However, what if carbon dioxide has a direct health effect on animals?

Studies suggest that elevated carbon dioxide concentrations can have detrimental effects on our health. One problem it appears to cause is oxidative stress, which is thought to underlie many of the health problems we face. Carbon dioxide exposure in an office environment at levels above 1000 parts per million leads to elevated levels of urinary 8-OHdG, compared to exposure at levels below 600 parts per million. The size of the effect is comparable to that of being a tobacco smoker. Other studies confirm that signs of oxidative stress begin to increase, long before concentrations of 1000 parts per million are reached.

If carbon dioxide exposure leads to increased urinary 8-OHdG levels, this is very worrying, as 8-OHdG is commonly used as an indicator of a variety of health problems. Elevated levels are indicative of atherosclerosis risk, cancer risk and complications seen in diabetes. Elevated levels of this marker of oxidative stress are also found in male patients suffering from low fertility. It’s notable that human sperm counts are believed to have decreased by 50% during the 20th century.

The question we have to ask ourselves is: What kind of future are we setting ourselves up for? Even our best case scenarios lead to levels above 500 parts per million, before 2100. Shell no longer believes that temperature increase will be kept below two degree Celsius, rather it predicts an increase of four degree Celsius, later rising to six degree Celsius.

A rise in temperatures by six degree Celsius, also means an increase in atmospheric carbon dioxide levels to above 1000 parts per million. In such a world, humans are chronically exposed to high levels that are known to detrimentally affect our mental abilities. We would feel continually uncomfortable and unable to think clearly. If carbon dioxide is responsible for oxidative stress symptoms, a world with such high CO2 concentrations would be one where people age prematurely and chronic disease affects us at ever younger ages. It’s difficult to see how humans could ever survive on such a planet.


The Stress of Global Warming on Human Health: pH Homeostasis

Significantly, earlier human studies have shown that chronic exposure to CO2 at moderate inspired concentrations alters pH homeostasis, and fosters body CO2 storage at the expense of buffers protein and phosphates in lean body mass, as does higher atmospheric CO2 concentration in the terrestrial biosphere. Increased CO2 stores matching lower bone mineralization characterizes Osteoporosis, a major public health problem whose risks for osteopenia, and non-spine fractures are significantly higher for people with higher percentage of body fat. Increased CO2 storage is present also in obstructive sleep apnea, a prevalent disorder characterized by gradual elevations of the partial pressure of CO2 in the arterial blood, associated with major nocturnal hemoglobin desaturation, higher HbO2 affinity, and repetitive episodes of partial or complete upper airway obstruction. Most individuals with obstructive sleep apnea have metabolic syndrome, term describing the clustering of abdominal obesity with other risk factors for atherosclerotic-cardiovascular disease (ACVD) which show abnormal intracellular ion profile in red blood cells, and sustained cortisol levels as does chronic exposure to increased ambient CO2. Studies suggest that moderately increased endogenous CO2 may oxidize erythrocytes, and promote their suicidal death (eryptosis) which, by fostering the release of pro-inflammatory cytokines throughout systemic circulation, activates hormonal stress response, and results in increased CO2 stores, abdominal fat accumulation, and Metabolic Syndrome. Ominously, Global Warming is an unbearable stress for ecosystems and their member species, just as this cluster of ACVD risk factors is for human health. This review focuses on Metabolic Syndrome and pH homeostasis, the linkage between breathing and feeding via CO2 economy, to disclose the Stress of global Warming on human health.

Earlier human studies have shown that chronic, continuous exposure to CO2 at 0.5-3% inspired concentrations for more than one month alters pH homeostasis and raises body CO2 storage [15,16,17], as does higher atmospheric CO2 concentration in the terrestrial biosphere. Mostly during CO2 exposure, ion profile changes in red blood cells (RBCs); hemoglobin-O2(HbO2) affinity increases with RBCs oxidation; the adrenal cortical response is activated, as measured by increased blood corticosteroid level and lymphopenia; and the partial pressure of CO2 in the arterial blood (PaCO2) rises as CO2 is stored as HCO3- in the extracellular fluid (ECF), and as CO3-2 in bone, at the expense of buffer protein and phosphate in the lean body mass (LBM) [15,16,17]. Continuous CO2 inhalation is commonly thought to be tolerated at 3% inspired concentrations for at least one month, and 4% inspired concentrations for over a week. The effects produced seem reversible, decrements in performance or in normal physical activity may not happen at these concentrations [18].

Thus, it should be noted not only that CO2 levels in poorly ventilated spaces can be found even higher than this range of 3-4%, but also that humans may be chronically exposed to intermittent, not continuous CO2 inhalation, a condition that by inducing mildly increased endogenous CO2 may cause pathological adaptations. In fact, studies show that because of the greater concentration of buffer base, acclimatization to CO2 results in desensitization of dyspnea and in changes of set point for central respiratory controllers such that, on return to “outdoor” air breathing, ventilation may decline below control values even in individuals intermittently exposed to CO2 increase for 13 hours per day [15,19]. Furthermore, chronic exposure to intermittent, mild ambient CO2 increase results also in changes of set point for central feeding controllers which may lead to obesity. In fact, it has been shown that during chronic inhalation of CO2 at 1.5% inspired concentration for more than one month, food intake decreases significantly, by ~30%, but body weight does not change [17]. On return to “normal” air breathing, food intake rises and body weight is gained [20]. Actually, stress is a well known inducing factor of both transient and chronic loss of appetite or overeating [21].

Inhaled CO2 induces the same physiological effects as does metabolically produced CO2, the key chemical messenger gas in the linking of respiration, systemic circulation, and local vascular response, to body’metabolic demands both at rest and exercise [18]. Increased CO2 needs to be removed as quickly as possible because its lowering of blood pH can denature enzymes. A major portion of the physicochemical defenses of neutrality by the buffer systems of the whole body takes place in muscle and bone [24]. Protein from muscle can be released to bind with acids in the blood. This can contribute to LBM loss. Calcium and phosphorus in bones can bind to acidic substances to neutralize them, thereby contributing to bone mineral loss. Suggestively, greater CO2 stores matching reduced bone mineralization characterizes Osteoporosis, a major public health problem whose risks for osteopenia, and non-spine fractures have been shown to be significantly higher for people with higher percentage of body fat [25]. Increased CO2 storage is present also in obstructive sleep apnea (OSA), a prevalent disorder characterized by gradual PaCO2 elevations, associated with major nocturnal hemoglobin desaturation, higher HbO2 affinity, and repetitive episodes of partial or complete upper airway obstruction [26]. Most individuals with OSA have metabolic syndrome (MetS), a common, condition consisting of a constellation of metabolic risk factors for atherosclerosis and cardiovascular disease (ACVD) associated with abdominal obesity, namely, increased plasma glucose values, higher blood pressure levels, higher triglycerides levels, and lower high-density lipoprotein cholesterol (HDL-C) levels [27]. The MetS presents abnormal intracellular ion profile in RBCs, and sustained cortisol levels [28,29] as does exposure to CO2 at 1.5% inspired concentrations for more than one month [17,30].

As stated, CO2 acclimatization to chronic exposure to CO2 at 1.5% inspired concentration results in greater concentrations of buffer base, with the consequent reduction of minute volume ventilation, forced vital capacity, and PaO2 [15]. Beyond that, food intake rises, and body weight is gained, on return to “normal” air breathing [20], as compared to exposure to moderately increased ambient CO2 in which lower (~30%) food intake, without body weight changes, matches increased ventilation [17]. Accordingly, adaptations to chronic exposure to intermittent, mildly increased ambient CO2 may result in lower O2 uptake, reduced metabolic rate, and excess feeding, as it occurs in MetS. Food intake may rise because mildly increased endogenous CO2 enhances the expression of TNF-α and IL-6, which further glucocorticoids release, with consequent higher expression of the oroxigenic NPY. Hence, CO2 does not only determine the need for alveolar ventilation, but it is also the “stress” ruler of both transient and chronic overeating or loss of appetite [21], to normalize/oppose pH changes.

With moderately increased endogenous CO2, as soon as RBCs oxidation threatens pH homeostasis, TNF-α may induce the coincident appearance of MetS ACVD risk factors [97] to restore the lost balance. In essence, TNF-α inhibits auto-phosphorylation of tyrosine residues of insulin receptors and promotes serine phosphorylation of insulin receptor substrate-1; this, in turn, triggers serine phosphorylation of insulin receptors in adipocytes, prevents the normal tyrosine phosphorylation, and interferes with transduction of the insulin signal. Hence, insulin resistance results in Akt (protein-kinase-B) inhibition and subsequent
inhibition of NO-synthase (NOS) [97]. Accordingly, TNF-α promotes adaptations such as insulin resistance-hyperglycemia, NOS inhibition, reoccurrence of glycolysis, and decreased O2 uptake whose joined effects overall reduce RBCs oxidation and maintain blood O2 release. Inflammation is, indeed, a fundamental survival mechanism but it is dangerous when its transient, physiological adaptations are converted to a long-lasting, pathological state. Potential causes for steady CRH activation and glucocorticoids release include environmental stresses, which as explained, result in higher HbO2 affinity and mildly increased endogenous CO2 [23]. Ominously, as atmospheric CO2 increases, Global Warming may threaten human health. Thus, the following reviews the mechanism through which intermittent exposure to mildly increased ambient CO2 may lead to MetS and/or osteoporosis.

Overall, during exposure to mildly raised ambient CO2 levels, slow adaptive processes in electrolyte exchange and pH regulation results in higher PaCO2 due to reduction in forced vital capacity. Presumably, food intake decreases much to reduce PaCO2, and body weight does not change [17] due to the water retention required to hydrate and store the inhaled CO2 as ECF HCO3-, and as bone CO3-2. Basically, with CO2 acclimatization, compensatory processes for respiratory acidosis result in metabolic alkalosis [107] which, on return to “normal” air breathing, constantly triggers glucocorticoids release. In fact, with abdominal accumulation, a lower compliance of the respiratory system causes the decline of forced vital capacity, minute volume ventilation, and PaO2 [15], with ensuing chronic lactate accumulation. This, by raising HbO2 affinity, results in higher PaCO2[49], and RBCs oxidation with TNF-α and IL-6 release from phagocytic cells. Besides, the relentless LBM loss coupled to the body fat gain arisen during exposure to CO2 implies not only that HbO2 affinity rises, and O2 release falls because the loss of body phosphate impairs 2-3DPG synthesis [53], but also that adipocytes release TNF-α and IL-6. Presumably, on return to normal air breathing, food intake rises, and insulin resistance persists until an ampler number of adipocytes release enough leptin which lowers bone formation and food intake without respiratory depression. In few words, with chronic exposure to intermittent, mildly increased CO2, body buffers loss sets a vicious cycle in which the more CO2 is inhaled and stored, the more food is eaten to raise PaCO2, foster ventilation, and save pH homeostasis.
With time, however, steady activation of the stress response leads to the loss of bone and muscle which, due to parallel abdominal fat accumulation, causes shallow, rapid breathing (not conscious tachypnea), turns up the set point for central feeding controllers, and induces overeating with its chronic pathological consequences, namely, MetS and osteoporosis.

Chronic exposure to CO2 at 0.5-3% inspired concentrations alters pH homeostasis and fosters body CO2 storage in humans [15,16, 17], as does increased atmospheric CO2 in the terrestrial biosphere. Increased CO2 stores in bone are present in osteoporosis, whose risks for osteopenia, and non-spine fractures have been shown to be significantly higher for subjects with higher percentage body fat, independent of body weight [25]. Fat accumulation and increased CO2 stores characterize also MetS which, despite lifestyle changes and the use of pharmacologic approaches to lower plasma cholesterol levels, continues to be, and it is expected to become the major cause of disability and death in the world by 2020 [108]. So far, it seems undeniable that pH homeostasis, the linkage between breathing and feeding via CO2 economy, discloses the stress of Global Warming on human health.


Chronic Respiratory Carbon Dioxide Toxicity: a serious unapprehended health risk of climate change

The earth’s atmosphere has already reached CO2 levels that are outside the range breathed by humans throughout their evolution. As well, in earlier pre-primate epochs, elevated atmospheric CO2 has been found to be a cause of mass extinction events (Knoll et al. 1996)

Despite significant documentation of health issues due to CO2 in indoor environments, there is minimal awareness in the community. For spacecraft and submarines there are practical considerations that influence the recommended safe levels. Initial safe limits for the International Space Station were partly decided by engineering requirements (Cronyn et al. 2012) and submarine limits were balanced by the ability to surface and renew air quality. It seems that there has been little concern about low-level toxicity of CO2 because we have always had the back-up of an ambient atmosphere with low levels of CO2.

As mentioned previously the body compensates for high levels of CO2, through a combination of increased breathing, blood pH buffering, kidney and bone adaptations depending on the length of continuous exposure, until we can resume breathing lower levels of CO2.

One author suggests that blood pH would be reduced to dangerous levels, if there were no physiological compensation, at CO2 levels as low as about 430 ppm (Robertson 2006) implying that compensation would occur at this level. Ambient conditions may already be dangerously close to CO2 levels that will induce continuous body compensation. Moreover, there is strong evidence that, with chronic activity, compensation mechanisms can produce serious health issues such as kidney calcification and bone loss.

It is conceivable that these problems might appear at much lower levels of CO2 if compensation persisted for a much longer periods, for example living a whole lifetime in an elevated CO2 atmosphere of a climate changed future. In the final paper of the US Navy CO2 research program, Schaefer (1982) indicated that this issue had “become the concern of the Department of Energy and other US government agencies” although it appears to have been largely forgotten (or classified) since.

If allowed to persist, problems such as kidney calcification could lead to renal failure. In the extreme case lifespans could become shorter than the time required to reach reproductive age. This could threaten the viability of human and animal species without interventions such as the creation of artificial living environments.

The human species is already impaired in indoor environments and this is likely to get worse as rising outdoor levels of CO2 contribute to increased indoor concentrations. Furthermore, the incidence and prevalence of human kidney calcification (i.e. stones) is increasing globally with the rate highest for males (Romero et al. 2010). Although this may not be related, it is possible that rising office levels of CO2 is a contributing cause. As well there is evidence that CO2 toxicity contributes to a range of serious health issues including cancer, neurological diseases and sleep disorders, and is being experienced by individuals at the current ambient levels which are now 40% higher than pre-industrial levels. It seems likely that CO2 toxicity related to human-induced climate change is already having an unrecognised impact on population health.

From the evidence presented here, there appears to be current health impacts of rising CO2 levels and a significant risk of serious health issues arising in the human population at some time in this century.

 This means that most humans could at this time be experiencing persistent body compensation for acidosis effects resulting in serious health problems. The risk for human and animal population health in the near-future is extremely high and should be communicated since global awareness of this issue may enable a change in CO2 emission activities.