Climate Change — A Glimpse Into the Science of Cataclysm (Part III)
An Explanation of What the Scientists Told Us Decades Ago but Which We Chose To Ignore Anyway (Yeah, Very Bad Idea)
This series on climate change has FIVE parts.
In Part I of this series we were introduced to the essence of the unfolding climate change crisis and saw how its greenhouse gas scientific underpinnings could be traced back more than 150 years.
In Part II we looked for clues as to what we might expect to happen in the coming decades based on what has happened in times past when the concentration of greenhouse gases in the atmosphere was similar to what we see today.
The prediction was that we will shortly commit ourselves to a world that is eventually entirely free of ice.
In Part III (this page) we look at the implications of this idea.
LIFE ON AN ICE-FREE PLANET EARTH
What might the world look like eventually if we continue to burn fossil fuels and destroy carbon-absorbing ecosystems so that carbon dioxide levels keep rising and the average global temperature rises to 4 or 5 degrees Celsius above pre-industrial times?
Four to five degrees is about the difference between where we are now and the last ice age. In terms of climate it represents a vast gulf.
Because of this it is probably not too far from the truth to speculate that in a 5 degree world fire would be almost as common an occurrence in the currently forested areas of the new world as ice and snow was in the last one.
In July of 2018 as I was writing this series the thermometer outside my apartment reached 46 degrees Celsius. This was 11 degrees higher than the average for that time of the year.
Much of the Northern Hemisphere was experiencing a lingering heat wave.
To the north, dozens of large-scale fires were burning on the Western forested landscapes of the United States. Likewise in the northern forests of East Siberia bordering the Arctic Circle, where much colder weather is expected, a heat wave with temperatures surpassing 35 degrees Celsius was fueling massive wildfires.
In Sweden the heatwave caused wildfires which burned more than 10 times the area of land they normally would during summer.
This kind of extreme climate behavior is representative of a world barely 1.1 degrees Celsius above pre-industrial. It may be sporadic behavior, but it will become increasingly more frequent in the years ahead as the average global temperature continues to rise. Baking heat, drought, year-round fire season.
Whatever lies ahead for us, you can bet we have absolutely no appreciation of what it will mean to live in a 5 degree Celsius world.
How could we? The last time it was that hot on this planet was 14 million years ago when the world was ice-free.
IMPENDING LOSS OF ANTARCTIC AND GREENLAND ICE SHEETS
The massive ice sheets of Antarctica had by that stage already formed once 20 million years earlier still, then they thawed out for a period of millions of years when CO2 levels rose once again, then finally they settled into a permanent frozen state which has existed until today.
To put these timelines into perspective, consider that our remote ancestors stood upright for the first time less than 2 million years before we (homo sapiens) appeared on the scene maybe a quarter million years ago. Throughout our entire history we have mostly known temperatures which have ranged from absolutely frigid to mildly tropical. We have never known real heat, the kind that will melt the infrastructure of societies.
Once the Earth settles into its new equilibrium, we can expect a 5 degree Celsius world to again be iceless.
It might take thousands of years to get to that iceless state. Possibly less. We do not know for certain. What we can say is that when the ice is gone our shorelines will be utterly transformed [Ref. SEALEVEL].
We know this because all the melted ice from Greenland, Antarctica, and all the remaining glaciers of the world, will raise sea level by an estimated 75 meters (250 feet).
We can confirm this astonishing result ourselves by doing a little “back of the envelope” calculation using numbers pulled off an internet search and restricting our calculation to just the largest contributor to the world’s ice (about 90 percent) which is the Antarctic ice sheet.
Our starting parameters for the calculation:
● The Antarctic covers an area roughly 5.4 million square miles● The oceans of the world cover 140 million square miles● The average depth of the Antarctic ice sheet is 2160 meters
From these numbers we determine that the oceans of the world cover an area 26 times larger than the Antarctic. Therefore, if the Antarctic ice were spread out evenly over the surface of the ocean its height would be reduced by a factor of 26.
So its height would be 2160/26 meters, or 83 meters.
But that is ice. When Antarctica melts we will be dealing with water which has 90 percent the volume it does as ice. So the final height of the water column would be 0.9 times 83 meters, or about 75 meters. This is higher than we would expect given that we have only included Antarctic ice. But for a rough calculation that does not take into account flooding coastlines it does confirm that the planet would be a significantly different place if all the ice melted.
To accept that we will transition to a 5 degree world is to accept the loss of dozens of our major population centers. London, Paris, Berlin, Stockholm, Amsterdam, St. Petersburg, Rome, Beijing, Shanghai, Tokyo, Boston, New York, Norfolk, Charleston, Houston, Miami, San Francisco, San Diego. These cities, and many more, submerged beneath the rising waters.
Even if we “only” transitioned to a 3 degree Celsius world we would likely be looking at flooding to a depth of several meters, perhaps dozens.
One way to get a better estimate of what we might expect for sea level rise in the decades ahead is to look at the period known (in Europe) as the Eemian, or (in the United States) as the Marine Isotope Stage 5e (MSI 5e). This refers to the peak of the warm period occurring before the last ice age. This peak windows the period of time between about 130,000 years ago and 115,000 years ago.
Paleoclimate researchers have studied fossilized coral reef formations from this period [Ref. HEARTY] and come up with a sea level curve accurate to about one meter:
In the graph above time increases from right to left as the world emerges from the ice age (interval #1) prior to the last and melting ice-sheets around the planet raise sea level until a point of stabilization is reached around 132,000 years ago (beginning of interval #2).
You can also see from the graph that sea level during the next 14 thousand years rose to as much as 9 meters beyond what it is today (during the short interval #5). The higher sea level (greater ice-sheet melting) suggests the average global temperature was warmer during this period, determined through other studies to be at its peak up to about 3 degrees Celsius beyond pre-industrial temperature. And yet the measured carbon dioxide levels for this time remained about the same as for pre-industrial, at roughly 280 ppm (consistent with no relative warming due to changing greenhouse gas levels).
So what explains the higher temperatures and extra sea water which can only have come from ice melt in Greenland and Antarctica?
The answer is that the higher temperature was the result of an extra radiative forcing due to the roughly 100,000 year long cyclical change in the Earth’s passage around the Sun, and the Earth’s axis of rotation, known as the Milankovitch cycle [Refs. MILAN1,MILAN2,MILAN3]. This is the same forcing that snapped the planet out of the ice age just prior to the Eemian. This solar irradiance, or insolation (or heating), was even larger at its maximum than for the ice age from which we emerged some 12,000 years ago. An excellent five-part discussion of the causes of sea level during the Eemian, written by Earth Sciences advocate Steve Brown, can be found on the Skeptical Science blog [Ref. BROWN1].
The Eemian radiative forcing reached a maximum around 125,000 years ago, then dove to a minimum a few thousand years later, initiating the last ice age.
For a period of about 6 thousand years (interval #2, beginning around 132,000 years ago) sea level remained remarkably stable at about 2.5 meters higher than today, while the temperature hovered at perhaps 1.5 degrees Celsius above pre-industrial. Later the temperature climbed to about 3 degrees Celsius around the 120,000 year mark and sea level shot up to as much as 9 meters higher than today (though could have been as low as 6.6 meters due to tectonic plate uplift — so there is some wiggle room here on how much ice disappears in the 3 degrees Celsius world [Ref. KOPP]).
The gradual changes in the sea level curve likely represent melting of Greenland and the Antarctic, whereas the sudden changes indicated by “notches” in the image above likely mark ice-shelf collapses in West Antarctica, where sea level rose quickly by a meter or more. Both Greenland and the West Antarctic are believed to have contributed at least 2.5 meters worth of sea level rise due to melt/collapse, though not necessarily at the same time [Ref. KOPP].
This coral reef-obtained sea level history suggests that if we get close to a 3 degrees Celsius world before the end of this century we might anticipate far greater changes to sea level than what would be expected on the basis of slow melting of ice-sheets (on land) and ice-shelves (in water) which could take centuries. Ice-shelf collapse could add several meters to sea level in a relatively short amount of time and wreak havoc with the shorelines of the world. Coastal cities would be flooded — not necessarily overnight as it takes time for water to redistribute around the globe, but also not on the order of centuries.
This ice shelf collapse-based projection of sea level rise is a far cry from the maximum estimate of 0.5 to 1.0 meter rise by the year 2100 derived from melt projections and thermal sea water expansion. Most estimates of the effects of climate change on the world’s ice reservoirs do not take into account collapse scenarios, just melting.
NOTE: Greenland’s existence, or more specifically the 2–3 kilometer-thick ice sheet that sits atop it, is something of an anomaly. It represents the only remaining fragment of the Northern Hemisphere ice sheets from the last ice age. It contains approximately 3.3 million gigatons of ice and will disappear from the face of the planet long before the Antarctic ice sheet which holds closer to 26.5 million gigatons of ice [Ref. ICEVOLUME]. Though the West Antarctic (largely marine ice) will disappear long before Greenland does — before the year 2200 and contributing about 5 meters to sea level rise, if current fossil fuel-burning trends are maintained, according to a 2016 computer simulation of realistic ice-ocean-atmosphere dynamics [Ref. POLLARD]IMPENDING LOSS OF ARCTIC SEA ICE
Regardless of the final height of the water column in the decades and centuries ahead, we will feel the effects of the current warming long before the loss of Greenland and Antarctic ice. We will feel it when the sea ice of the Arctic ocean disappears for good sometime within the next couple of decades. Even today polar observers watch the ice anxiously every summer for signs that this year might mark the last one for which some appreciable portion of ice manages to remain solid the entire year round (you may be reading this article and observing to yourself that this “blue ocean” event, where ice is replaced by open water, has already taken place).
In the last few decades Arctic sea ice has retreated from year-round cover, to a summer-time low in September of less than half that amount, and a drop in ice volume by perhaps three quarters. The disappearing north pole sea ice has been one of the most visible signs of impending climate catastrophe.
In 2012 the retreat of summer sea ice was particularly notable, dipping lower in September of that year than any prediction to come out of sea ice loss modeling.
Extent is the term used to describe areas of the Arctic and Antarctic oceans where more than 15 percent of the surface is covered in ice. For the most part it is assumed this “fuzzy” cataloging of the amount of ice cover is only unreliable around the boundaries of the ice sheet.
Until recently the historical record of Arctic sea ice extent was not well known, making it difficult to speculate on just how much recent global temperature increases have been contributing to the shrinkage of the ice. Satellite coverage of the region began in the late 1970s but before that direct measurements of sea ice extent are sparse.
But in 2016 a record was painstakingly reconstructed by Florence Fetterer and colleagues at the National Snow and Ice Data Center [Ref. ICEBRIEF]. They used data collected from various maritime sources going back as far as the year 1850, including ship and aircraft observations, newspaper, diary, and whaling ship log books, and a host of data gathered from institutes which sent observers to study the area over the years.
To the untrained eye this sea ice extent reconstruction may not appear very dramatic. But what it shows is that until about 1930 Arctic summer sea ice had been remarkably stable. Then it began to fluctuate uncharacteristically before entering a shrinking phase from which it has never recovered.
In the years since about 1970, as the planet has warmed, the summer extent has almost halved, and continues to disappear at a rate of about 13 percent per decade.
Computer models predict that summer sea ice extent will bottom out at around 1–2 million square kilometers, down significantly from its pre-industrial value of approximately 9 million square kilometers which it last visited in the 1960s.
According to the models winter ice will disappear too, collapsing suddenly from its relatively stable high-extent values to something closer to the summer time extent numbers. All within the time frame of a few years. This scenario is expected to take place within the next couple of decades.
When the winter ice disappears the sunlight that had been reflected back into space by the ice for most of the year will be absorbed by the Arctic ocean. Clean, white ice reflects more than 80 percent of the Sun’s light, so that light never gets the chance to warm the Earth. Even dirty ice reflects about 60 percent of the light which falls on it.
But open ocean water absorbs all but about 10 percent. That means 90 percent of the energy of the sunlight is absorbed by the ocean and converted into heat.
This ability of a surface to reflect light is referred to as it’s albedo. The albedo of the Earth as a whole is slightly less than 30 percent, and planetary warming (or cooling) is critically dependent on this value.
Dr. Peter Wadhams, an Arctic sea ice expert with more than four decades of experience, has pointed out that when the Arctic ice is gone the effect on planetary warming due to the change in albedo will be about the same as the effect of all the greenhouse gases released into the atmosphere by man to date. In other words the rate of warming may double.
This is such an alarming observation that it’s worth trying to do a “back of the envelope” calculation to confirm it. I will cut to the chase and tell you the figure we are going to come up with is an increase in the rate of warming of 40 percent due to this effect (not double, but still very significant).
It turns out it is not a conceptually simple calculation to do. I had to repeat the effort several times, coming at it different ways, before I was reasonably confident I had included the main effects. So take the following result with a grain of salt. My answer for the amount of increased warming could easily be off by a factor of two or so. Nonetheless, the exercise is instructive. It vividly demonstrates the problem.
We begin with the observation that the amount of solar energy falling onto Arctic sea ice in mid summer is about 220 watts per square meter (W/m**2) [Ref. ARCTICSUN]. We reduce this by a factor of two to account for the fact that half the year the Arctic is in darkness. This gives 110 W/m**2 as the average strength of the Sun as a warming influence in the Arctic.
If we assume the average albedo of ice is about 70 percent, and that it is replaced by 10 percent when the ice melts [Ref. ARCTICSUN], then the increase in energy absorbed into the ocean is equal to the fractional reduction in albedo, which is 0.6, times 110 W/m**2 — or 66 W/m**2.
If summer sea ice extent ultimately falls from 9 million to 2 million square kilometers the difference in the area of exposed Arctic ocean will be roughly 7 million square kilometers. In comparison, the surface area of the Earth is 510 million square kilometers.
So the ratio of the two areas is 510/7 or about 73. We divide our estimate of the increase in energy per unit area by this ratio to get the average global increase in radiant energy due to the loss of reflective Arctic sea ice.
It comes out to 66/73 W/m**2, or 0.9 watts per square meter.
Currently the accepted rate of excess heating due to all anthropogenic (man-made) factors, including greenhouse gases released into the atmosphere since the beginning of the industrial age, is in the vicinity of 2.3 watts per square meter [Ref. RADFORCE]. This number also takes into account the effect of “anti-greenhouse” gases, like aerosols which act to cool the planet rather than warm it (sulphur dioxide being one of the best known of these gases).
Thus our very rough calculation has come up with an extra melted sea ice planetary warming contribution roughly FORTY PERCENT as large as the currently accepted global warming figure due to all other factors. Because we have ignored the reduction of albedo on the land around the Arctic sea, due to loss of snow coverage, our number is probably a good lower limit to the true extent of the additional warming.
So for the sake of argument, let us assume this estimate of ours is correct. The combined “radiative forcing”, which is the scientific term for the overall heating from solar radiation, will thus be about 2.3 + 0.9 = 3.2 watts per square meter.
What is the significance of this number?
Dr. James Hansen, an authority in climate science, stood before the U.S. Senate in 1988 and declared we were already seeing the effects of global warming due to human-caused greenhouse gas emissions. He proclaimed at the time that we would see a great deal more warming in the decades ahead (about which he has turned out to be correct).
In a paper in 2008 detailing the effects of C02 on climate throughout the Earth’s history Hansen and others pointed out that it was a radiative forcing of just 3.5 watts per square meter that forced the Earth to transition out of the last ice age into the stable “0 degree world” we enjoyed for the 10 thousand year period leading up to the industrial age [Ref. HANSEN2008].
Three and a half watts of heating raised the Earth’s temperature by 4 degrees Celsius. Hansen also pointed out that it would take an excess of just 4 watts per square meter to reach a new equilibrium in which all the ice of the world is completely melted.
So when the Arctic summer ice shrinks down to 2 million or so square kilometers we will “jump” half of the way from where we are now to the state that eventually implies an ice-free world. In fact, by the time we get to this “midway point” (around the year 2040) the amount of C02 in the atmosphere is likely to have surpassed 460 ppm and the CO2 forcing will have increased by about another 0.6 watts per square meter (half that amount per decade [Ref. AR5CHAP8]). We will be close (at 3.8 watts per square meter in 2040) to the equilibrium forcing of 4 watts per square meter that Hansen believes is required to fully melt Greenland and Antarctica (again, note that we have not included the forcing due to the loss of albedo on land around the Arctic sea, or the expected increases in forcing due to methane or any other greenhouse gases during this period).
In all likelihood, somewhere around 2040 to 2050, we will find ourselves committed to an iceless 5 degree Celsius world where sea level will eventually rise over 200 feet. This is not science fiction. This is not “maybe”. This is basic physics matched up with observation of the historical sea level, sea ice extent, temperature, and greenhouse gas records.
What does it mean that the total radiative forcing, or warming of the planet, is currently 2.3 watts per square meter?
Well, in a world in energy equilibrium, as we expect was the case before humankind appeared on the scene and began upsetting the landscape and the air above it, the net radiative forcing would have been zero. Each day as much energy would have been radiated back into space as was absorbed from the Sun.
We can calculate how much energy we are currently absorbing each day today due to the imbalance. For the calculation we will need to be aware of the following:
● one watt = one joule per second (a joule is the standard unit of energy)● the surface of the Earth covers 510 million square kilometers, or 510 trillion square meters● the number of seconds in a day is given by 24 hours times 60 minutes per hour times 60 seconds per minute, or 86,400
So 2.3 watts per square meter applied to every square meter of Earth’s surface for a 24 hour period gives us the total daily energy imbalance of the world.
It is 2.3 times 86,400 times 510 trillion joules, or roughly 100 million trillion joules. Not zero, as it once used to be.
For comparison purposes, the energy released by the atomic bomb which destroyed the city of Hiroshima in 1945 was estimated to be equivalent to 15 kilotons of TNT, or 63 trillion joules. Divide that number into our daily planetary energy imbalance and we find we are absorbing the energy equivalent of 1.6 million Hiroshima bombs.
Let that figure sink in for a moment.
For every day that passes now the potential destructive energy being absorbed by the Earth is equal to the energy of 1.6 million small atomic detonations. This is why climate scientists sometimes sound like alarmists — because they know you cannot expect to add this much energy daily to our planet and not expect some serious consequences as a result.
Because of the large heat capacity of the oceans and the fact that it is taking the bulk of this energy imbalance, we have so far been spared a great deal of the consequences. But this good fortune cannot last forever. Sooner or later, we as a species, will pay the energy debt. Or our children will.
The tragedy is that scientists have been able to figure out well ahead of time that there will be serious trouble ahead for humanity if it does not change its environmentally destructive ways.
But so far to no avail. The scientists have warned the world, and the world either is not listening, or is incapable of comprehending the scope of the environmental disaster that will proceed to unfold in slow motion.
One of the most obvious consequences: if no action is taken all the coastal cities of the world will be lost and coast lines moved inland as much as several hundred miles.
Already the contribution to global warming due to vast stretches of open (ice-free) Arctic ocean in the summertime months is estimated to be 25 percent of the current contribution due to greenhouse gases alone.
If this projected increase in the rate of global warming does not scare you, it should.
This loss of Arctic albedo (sea ice) is happening right now. It has been happening for decades. And there is good reason to believe that we as a species will not begin to take serious action on climate change until AFTER that sea ice has gone, the rate of warming has increased to more than one and a half times what it is today, and that oh-so-remote year 2100 future is coming at us faster than anyone expected it possibly could.
IMPENDING LOSS OF FRESH WATER SUPPLIES
Nor is it just the ice which is disappearing. Our fresh water supplies are going too.
One of the consequences of a warmer atmosphere is higher evaporation rates from the surface of the land. This increases the frequency and duration of droughts.
On top of this, the loss of Arctic ice increases the likelihood of extreme drought because of a complex interplay between the masses of Arctic-generated cold air, and the warm air which flows north from the equatorial regions.
Less ice in the Arctic reduces the difference in air temperature between the Arctic and the equatorial regions. The effect of this is to destabilize the “jet stream”, the river of Arctic cold air that ordinarily cools water vapor and drops snow at high altitudes on the land.
With a destabilized jet stream the warm air from the equatorial regions forces the cold Arctic air to make unusual excursions from its historical route across the top of the world. This causes the cold air to more frequently miss its historical targets and dump snow where it is currently not needed. For example, instead of putting snow onto the Sierra Nevada mountains in Northern California, that snow might end up on the Rocky mountains, or further east still.
The conclusion of climate scientists in 2004 was that “decreased Arctic sea ice causes drying of western North America”. Like Peter Wadhams, these researchers had begun asking questions about what effect the loss of sea ice from the Arctic might have on climate at remote locations in the year 2050 [Ref. DRY2004].
They saw that the shrinking albedo associated with more open ocean water in the Arctic would contribute significantly to the rate of warming in the region, and that ultimately this would affect the delivery of storm tracks that deposit snow in western parts of the United States.
This is particularly bad news for Californians but also for other human populations elsewhere on the planet which depend on snow pack as a year-round source of fresh water.
Whereas until now we have relied on melting snow pack throughout the spring and summer months to fill riverways and dammed reservoirs, today we are looking at an ever-decreasing availability of fresh water.
Even when the jet stream does put cold air over mountain ranges the increased temperature due to global warming can cause precipitation (rain) rather than snow to fall.
The result is water that runs off the landscape during the winter months, creates problematic flooding, and is then lost to the oceans rather than being stored in frozen form until it is needed for agriculture and urban use (by thirsty humans) in the months ahead.
This is a real problem where I live in the desert region of Southern California. Forty million people here depend on snow pack for water. Unfortunately most of them have no idea where their water comes from (other than out of the faucet) or that it is under threat of going away in the near future. Snow pack in the Sierra Nevada mountains is projected to reduce by more than 50 percent before 2060 (and as early as 2040), and reduce by almost 80 percent by the end of the century [Ref. SIERRASNOW].
This trend in fresh water scarcity is expected to continue around the world and lead to a dramatic restructuring of the landscape.
The western half of the United States, largely irrigated desert at the moment, will be transformed under a 5 degree world into something resembling the waterless Dust Bowl of the 1930s — the next arid Sahara with protracted temperature extremes pushing close to 50 degrees Celsius [Ref. DROUGHT].
Even the size of the American desert will grow as the “100th Meridian”, the historical geographic divider between the humid east and arid west regions of the United States, the boundary between soils that can and cannot support crops without the aid of irrigation, “shifts” ever to the East.
Already since the year 1878 when the 100th Meridian was recognized as more than a line of longitude on a map of the U.S., the dry earth to the west of it has crept eastward about 140 miles into the 98th Meridian under the driving force of climate change.
Even if the boundary ultimately does not continue its eastward trek, certainly the difference in climate between the two regions is expected to sharpen, with increasingly dry conditions to the west and more frequent precipitation to the east. And everywhere it will continue to get hotter, especially in the summer months.
If you happen to live in one of these wetter areas, like the East Coast of the United States, you might think you have managed to escape the consequences of the fresh water scarcity problem. But in places where snow pack has always been scarce populations have tended to rely almost exclusively on drawing ground water for their source of fresh water, rather than build infrastructure to capture rain water.
The consequence of this is that ground water supplies in the United States and across most of the globe are almost exhausted [Ref. GROUNDWATER]. Once they run dry they will remain dry, as the natural ground water refill time is of the order of thousands of years. According to Scientific American [Ref. OGALLALA1]: “Today the Ogallala Aquifer (one of the largest in the U.S.) is being depleted at an annual volume equivalent to 18 Colorado Rivers.”
It is not hard to see how this might not be sustainable [Ref. WATERWARS]. By some estimates the Ogallala — from which water is drawn to produce about a sixth of the world’s grain crops — could be dry by 2040, and in some places by 2030 [Refs. OGALLALA2,OGALLALA3].
Worse yet, we apparently have so little regard for the impending water crisis that we are literally turning vast quantities of the remaining water supply into biofuels. In 2017 approximately 140 million tonnes of maize was converted into ethanol [Ref. FOODCRISIS]. It takes 147 gallons of water to grow just one pound of maize. Crunch the numbers and you find this represents an annual loss of 45 trillion gallons of non-replenishable water we will surely one day regret having squandered.
Nor will the loss of fresh water due to climate change affect just our drinking water supplies.
IMPENDING LOSS OF FOOD SECURITY
The effect of diminishing fresh water resources on farmland utility and crop yields, not only in the United States but elsewhere, is especially worrisome. The world relies on maize (corn), wheat, and rice for approximately half of all its calorie requirements. You simply cannot grow food without a reliable source of fresh water. So when the world goes thirsty, by necessity it also goes hungry.
But even in regions which do manage to efficiently tap every last drop of their fresh water supply crops are still susceptible to extremes of temperature.
It does not take an enormous increase in the average temperature of a season to destroy a crop yield [Ref. SHOCKS] [Ref. CORNSTRESS].
The reduction in annual harvest size for maize, wheat, and rice varies between about 3 and 17 percent per one degree Celsius of increased average temperature over the growing season.
In France in 2003, when the average temperature for the summer went up by 3.6 degrees Celsius, production of maize fell by 30 percent, wheat by 21 percent, and fruits (like grapes) by 25 percent. In Italy that same summer the maize yield fell by 36 percent [Ref. YIELD2003].
In 2018 drought parched the soils of Europe, resulting in overall grain losses in Germany by the end of summer of 26 percent. Some German farmers reported a 70 percent loss [Ref. GERMANDROUGHT].
This kind of historical record provides a glimpse into what we might expect as routine crop losses in a world perhaps 3 degrees Celsius above pre-industrial. It is one in which countries will regularly have to contend with shortfalls in food production. At the same time they may find their neighbors hard-pressed to come up with an excess of harvest to meet the food gap.
Nor are the largest of the world’s food producers likely to find themselves immune to crop losses. The United States will be particularly vulnerable, with summer temperatures regularly well beyond the 30 degree Celsius upper limit for sustainable wheat and maize yields. Extreme prolonged summer temperatures of 40+ degrees Celsius are likely to be routine by the middle of the century. Already U.S. farmers are wondering how they will be able to outsmart climate change in the coming decades, and they are less than optimistic about their chances [Ref. FARMERS].
At a time when the population of the world is expected to have grown by another 2 billion hungry mouths, the amount of available food is expected to fall by more than a quarter of what is currently produced. Combine heat stress with water stress and — unless we come up with radically more efficient ways to produce food in the years ahead— crops yields may be down by as much as one half of what they are today.
Given that an estimated 700–800 million people today already lack sufficient access to food, the expected shortfall in food production in the decades ahead spells disaster for a significant fraction of the world’s population. No nation is likely to be spared, though some will fare far worse than others.
The notion of soaring food prices and even food rationing in America may sound strange, but it is increasingly likely to become reality in a world subjected to rapid climate change.
It is because of growing concerns that such possibilities no longer seem to represent the “science fiction” they once did, that in 2015 the world finally sat up and took notice of the crisis that now appears to be headed towards us with very little room for doubt.
Next Up, in Part IV:
● THE PARIS AGREEMENT: HUMANITY'S LAST HOPE, OR CLIMATE MIRAGE?● SANITY CHECK — COULD THOSE WORRISOME TEMPERATURE PROJECTIONS BE WRONG?● RUNAWAY GLOBAL WARMING — IF NOT AVOIDABLE, THEN HOW SOON?● THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE MOVES UP THE TIMELINE FOR CONCERN
Click Here to Proceed to Part IV
REFERENCES[HAWKINS] Warming stripes (by Ed Hawkins)[ARCTICFIRES] The global heat wave as seen by satellites, airplanes, and weather stations[SEALEVEL] Earth Under Water Worldwide Flooding Sea Level Rise (Nat. Geographic)[HEARTY] Global sea-level fluctuations during the Last Interglaciation (MIS 5e)[BROWN3] The Last Interglacial Part Three — Melting Ice and Rising Seas[MILAN1] Is an Ice Age Coming? | Space Time | PBS Digital Studios (Milankovich cycles explained)[MILAN2] Milankovitch cycles[MILAN3] Dan Britt — Orbits and Ice Ages: The History of Climate (Youtube)[BROWN1] The Last Interglacial — An Analogue for the Future?[KOPP] Probabilistic assessment of sea level during the last interglacial stage[ICEVOLUME] Antarctic ice volume measured[POLLARD] Contribution of Antarctica to past and future sea-level rise[ICEBRIEF]Piecing together the Arctic’s sea ice history back to 1850[2040ICE] Will the Arctic be free of summer sea ice in 30 years?[ARCTICSUN] Present status and variations in the Arctic energy balance[RADFORCE] Climate Change Indicators: Climate Forcing (EPA)[AR5CHAP8] AR5 — Chapter 8: Anthropogenic and Natural Radiative Forcing[VORTEX] Polar Vortex: How the Jet Stream and Climate Change Bring on Cold Snaps[DRY2004] Disappearing Arctic sea ice reduces available water in the American west[GREENHOUSE] Endless Summer: Living With The Greenhouse Effect (Discover Magazine 1988)[SIERRASNOW] Water shortages ahead? Sierra Nevada snow pack on track to shrink 79 percent, new study finds[DROUGHT] Permanent drought predicted for Southwest[98MER] Dividing line: The past, present and future of the 100th Meridian[GROUNDWATER] PUMPED DRY: The Global Crisis of Vanishing Groundwater[OGALLALA] The Ogallala Aquifer: Saving a Vital U.S. Water Source[OGALLALA2] Drying times: Could the rapidly depleting Ogallala Aquifer run dry?[OGALLALA3] What Happens to the U.S. Midwest When the Water’s Gone?[WATERWARS] The Water Wars of Arizona[FOODCRISIS] How Can We Avoid A Food Crisis That’s Less Than A Decade Away[SHOCKS] Climate change could heighten risk of global food production shocks[CORNSTRESS] How Extended High Heat Disrupts Corn Pollination[YIELD2003] Historical Warnings of Future Food Insecurity with Unprecedented Seasonal Heat[GERMANDROUGHT] German Farmers Struck By Drought Fear Further Damage From Climate Change[95CDAYS] 95-Degree Days: How Extreme Heat Could Spread Across the World[FARMERS] Politicians say nothing, but US farmers are increasingly terrified by it — climate change
