The Climate Threat from Arctic Methane Releases


The Climate Threat from Arctic Methane Releases

A friend, who is an intelligent person with no science background, asked me to explain simply what the concern expressed with alarm by many scientists and (anti) climate change activists is about the increasing rate of methane gas emissions in the Arctic. That attempted explanation follows.

From even before the extinction of the dinosaurs by the Chicxulub Meteor 66 million years ago (66mya), to about 34mya, the Earth was much warmer (the peak occurred 50mya) and there was no polar ice, north or south.

Antarctica was covered in forests and jungles; the Arctic Ocean was a warm sea ringed by swamps and forests of ferns and Redwood trees along the Eurasian and North American northern continental shores; and those swamps swarmed with crocodiles.

Between 34mya to 12mya Earth’s temperature fluctuated and Antarctica froze thawed and refroze. Then Panama swung into place closing the oceanic gap between North (Central) and South America, and that altered ocean currents so that a Southern Ocean circumpolar current sealed off Antarctica climatically: the deep freeze of that continent that continues to this day.

That global cooling trend continued after 12mya and plunged Earth into the deep cold of the repeated glaciations of the Pleistocene Epoch (Ice Ages), from 2.58mya to 11,700ya, before the thawing of temperate latitudes introduced the balmy global climate we have enjoyed since.

All the lush and soggy vegetation around the Arctic Ocean was buried by sedimentation into the shallow continental shelves around that ocean, and then further locked away by the deep freeze producing permafrost, which extends quite a bit down below the ground surface, and down from the top of the seafloor of the shallows near land.

Rotting organic matter in the seas (algae, plants, fish, animals) sinks to the bottom and is decomposed by bacteria, and that produces methane gas (like cows fart from eating grass, and we fart from eating beans); but because of the cold and pressure deep down in all oceans, or in cold shallower seas like the Arctic, that gas actually combines with water into a fragile unstable crystal-like solid called methane clathrates or methane hydrates.

This is an “ice” that people can light up with a match and it burns like gas-soaked charcoal, but with a blue flame. When a methane hydrate solid is brought up to the surface of the ocean from the high pressure of the depths, it can spontaneously ignite because of the release of methane gas mixing with the oxygen in the air. Such flares have been seen on the ocean surface at night by airline pilots.

There is a large amount of compressed, frozen methane-rich organic matter, including peat, all along the sub-Arctic ring of sea and land about the Arctic Ocean. The thawing of that region is now increasingly releasing some of the trapped gas: from out of the clathrates, from out of subsurface compressed organic plant matter, and also from new underground fires burning peat seams and coal seams. Such fires are now extensive and burning continuously all along northern Siberia; they are called Zombie Fires.

Because of the complexities of molecular structure, a molecule of methane (CH4) has 2.5x (15/6) more ways of moving, plus rotating about and vibrating along the chemical bonds between its atoms, so as to store heat, than does a molecule of carbon dioxide (CO2). So, CH4 is 2.5x times more effective at being a global warming agent than CO2.

A large release of CH4 into the atmosphere will have a more pronounced global warming effect than an equal mass of CO2. But CH4 eventually combines with atmospheric oxygen molecules to form more CO2 and H2O (water).

What is happening in the Arctic is that the massive amount of stored subsurface methane — in all the forms that bound it — is now being warmed sufficiently to allow it to overcome the cold and pressure that used to hold it in. So there is an increasing rate of methane gas bubbling up from the seafloor, and from the Arctic tundra which is permafrost grassland that is thawing, slumping, and popping out with methane eruption craters, some tens of meters in diameter and depth. [1], [2]

Because of that accelerating rate of emission, and because the total amount of methane stored in the Arctic is so large, climate scientists are very concerned about the negative potential for our climate in the near future.

How worried? How fast? How alarming?

Well, the presently accelerating rate of carbon dioxide buildup in the atmosphere, and of global warming, is proceeding at a pace at least 20x that of previous major CO2 eruptions and global warming events in Earth’s geological past (like during the onset of the Paleocene-Eocene Thermal Maximum, 55.5mya); and that rate today could even be hundreds of times faster.

The CO2 increase in the atmosphere over the last century or so has equaled comparable amounts of increase that may have occurred over several thousand years during the massive eruption episodes in the geologic past that caused major extinctions.

During those past eruption events, where the pace of change was over thousands of years (a blink of the eye geologically), despite the extinctions that occurred much animal and plant life was able to adapt, and such adaptation carried on over longer spans of time was their transformation by biological evolution.

But today such a tactic of biological adaptation by a species in response to the shifting of climates is impossible because the genetic processes of evolution are far outpaced by the rapid rate of increase of CO2 concentration, and thus of global climate change.

However, we are not talking about doomsday in 5 or 10 years. Just think of how climate and weather have changed (gotten worse) since, say, the 1970s, and imagine a similar rate of degradation for another few decades, and you can then guess that sometime near the end of this century (maybe the 2070s) that Earth will really be at the edge of environmental collapse: if humanity had continue to do nothing about curbing its greenhouse gas emissions since this moment, and continues heedlessly emitting fossil fuel exhaust fumes beyond that point. 

Many people worry that such an unhappy timetable could be sped up if there were to be a truly massive eruption of “all” the methane locked up in the Arctic. If I get to live to be 100, in 2050, I’ll then know the ultimate course of Earth’s dynamic climate system.

Young people worldwide, sparked by Greta Thunberg [3], will be alive in 2050 and very much want to know NOW what the environmental conditions will be THEN, when they are supposed to experience their adult lives and be responsible for continuing civilization. And they have every right to demand that today’s adults do their intergenerational duty to pass on a hospitable Earth that sustains their dreams, our human civilization, and all species’s futures.

Within the next 10 years we had better begin to actually and continually cut down civilization’s (anthropogenic) annual CO2 emissions; by 25 years we had better be reducing them at a very pronounced rate; otherwise by 50 years Earth’s temperature may be high enough to trip the climate system into a new mode we will very much dislike — being much more of what we don’t like now — and which will be beyond our ability to correct regardless of whatever heroic measures we would then take, like miraculously dropping our CO2 emissions to zero forever.

The geophysical reality is that it takes the climate system hundreds of years (I once estimated 240 years) to BEGIN to shift in response to new atmospheric conditions. This is like a huge thermostat lag to a heating system of global scale, or like the lag between turning the rudder on a large ship and then actually having the ship begin to veer in a new direction.

It is because of this inertia that it is essential to stop our emissions as soon as possible (ASAP). The longer we wait — emitting more while waiting — the longer it will take Earth to respond to our finally throttling our emissions, and the longer it will take for the climate system to flush out that excess CO2 and lower the average global temperature. I estimate 1,000 to 1,400 years, but it could be much longer.

So that is what the worry about the increasing Arctic methane releases is all about.


[1] Giant new 50 meter deep crater opens up in the arctic tundra

[2] More than 300 sealed craters are ticking time bombs from a total of 7000 plus arctic permafrost mounds

[3] “I Am Greta,” an excellent documentary about the young lady who is puncturing the big phonies of all our governments, on the overarching issue of climate change.


Ocean Heat, From the Tropics to the Poles

The heat being captured by the increasing load of carbon dioxide and other greenhouse gases in the atmosphere is subsequently transferred into the oceans for storage. This process — global warming — has raised the temperature of the biosphere by 1°C (or more) since the late 19th century.

Heat introduced into any material body at a particular point will diffuse throughout its volume, seeking to smooth out the temperature gradient at the heating site. If heat loss from that body is slow or insignificant, then a new thermal equilibrium is eventually achieved at a higher average temperature.

Thermal equilibrium does not necessarily mean temperature homogeneity, because the body may have several points of contact with external environments at different temperatures that are held constant, or with other external thermal conditions that must be accommodated to. Equilibrium simply means stable over time.

The heat conveyed to the oceans by global warming is absorbed primarily in the Tropical and Subtropical latitudes, 57% of the Earth’s surface. The Sun’s rays are more nearly perpendicular to the Earth’s surface in those latitudes so they receive the highest fluxes of solar energy, and oceans cover a very large portion of them.

That tropical heat diffuses through the oceans and is also carried by ocean currents to spread warmth further north and south both in the Temperate zones (34% of the Earth’s surface) and the Polar Zones (8% of the Earth’s surface).

What follows is a description of a very idealized “toy model” of heat distribution in the oceans, to help visualize some of the basics of that complex physical phenomenon.

Heat Conduction in a Static Ocean

The model is of a stationary spherical globe entirely covered by a static ocean of uniform depth. The seafloor of that ocean is at a constant temperature of 4°C (39°F), the surface waters at the equator are at 30°C (86°F), and the surface waters at the poles are at -2°C (28°F). These temperature conditions are similar to those of Earth’s oceans. These temperature boundary conditions are held fixed, so an equilibrium temperature distribution is established throughout the volume in the model world-ocean. There is no variation across longitude in this model, only across latitude (pole-to-pole). (See the Notes on the Technical Details)

Figure 1 shows contours of constant temperature (isotherms) throughout the depth of the model ocean, from pole to pole. The temperature distribution is shown as a 3D surface plotted against depth, which is in a radial direction in a spherical geometry, and polar angle (from North Pole to South Pole).

Figure 2 is a different view of the temperature distribution. Three regions are noted: The Tropical Zone (from 0° to 23° of latitude, north or south) combined with the Subtropical Zone (from 23° to 35° of latitude, north or south); the Temperate Zone (from 35° to 66° of latitude, north or south); and the Polar Zone (from 66° to 90° of latitude, north or south).

The model temperature distribution is perfectly stratified — isotherms uniform with depth — in the Tropical-Subtropical Zones, from 30°C at the surface at the equator, to 4°C at the seafloor. On entering the Temperate Zones, the isotherms arc up into a nearly radial (vertical) orientation. In the small portions of the planetary surface covered by the Polar Zones the isotherms are now more horizontally stratified because the surface waters are chillier that the those at the seafloor.

Figure 3 shows the streamlines of heat flow (the temperature gradient) for this temperature distribution. At the equator the heat is conducted down from the 30°C surface to the 4°C seafloor. As one moves further away from the equator the streamlines become increasingly lateral, until they are entirely so at 35° of latitude (north or south) where the model surface waters are at 19°C. The heat flow is entirely horizontal at this latitude, which separates the Subtropical and Temperate Zones; tropical heat is being conducted laterally toward the poles. In the Polar Zones the heat flow is up from the lower depths because the surface waters are chiller than those at depth, and because there is too little temperature variation with distance along the surface to drive a lateral heat flow.

Thermally Driven Surface Currents

Much oceanic heat is distributed by currents, and many of these occur along the surface.

The average speed of the Gulf Stream is 6.4km/hr (4mph), being maximally 9kph (5.6mph) at the surface but slowing to 1.6kph (1mph) in the North Atlantic, where it widens (information from the National Oceanic and Atmospheric Administration, NOAA).

Heat-driven equator-to-poles surface currents on the model ocean were estimated from the combination of the pole-to-pole surface temperature distribution, and thermodynamic data on liquid water. (See the Notes on the Technical Details)

The pressure built up by tropical heat in the model ocean’s equatorial waters pushes surface flows northward (in the Northern Hemisphere) and southward (in the Southern Hemisphere): from a standstill at the 30°C equator; with increasing speed as they recede from the equator, being 2kph (1.3mph) where the surface waters are at 25°C (77°F); a continuing acceleration up to a speed of 2.8kph (1.7mph) at the 35° latitude (the boundary between the Subtropical and the Temperate Zones); and an ultimate speed of 3.6kph (2.2mph) at the poles.

The currents are converging geometrically as they approach the poles, so a speed-up is reasonable. Logically, these surface currents are legs of current loops that chill as they recede from the equator, plunge at the poles, run along the cold seafloor toward the equator, and then warm as they rise to the surface to repeat their cycles.

An equator-to-pole average speed for these model surface currents is 2.8kph (1.7mph). Their estimated travel times along the 10,008km surface arc (for a model world radius of 6,371km, like that of a sphericalized Earth) is 3,574 hours, which is equivalent to 149 days (0.41 year).

Greater Realities

The model world just described is very simple in comparison to our lovely Earth. Since it does not rotate, it does not skew the north-south flow of currents that — with the help of day-night, seasonal, and continental thermodynamic inhomogeneities — creates all of the cross-longitudinal air and ocean currents of our Earth.

The irregularity of seafloor depth on Earth also redirects cross-latitudinal (pole-to-pole) and cross-longitudinal bottom currents, as do the coastlines of the continents; and the very slight and subtle changes in seawater density with temperature and salinity — neither of which is distributed uniformly throughout the body of Earth’s oceans — also affect both the oceans’s volumetric temperature distributions, and the course of ocean currents.

Recall that the model ocean is bounded by constant imposed temperature conditions at its seafloor (4°C) and surface waters (a particular temperature distribution from 30°C at the equator, to -2°C at the poles). Since this model world is otherwise suspended in a void, if these boundary conditions were removed the oceanic heat concentrated at the equator would diffuse further into the watery volume, seeking to raise the temperatures of the poles and seafloor while simultaneously cooling the equatorial region. The ultimate equilibrium state would be an ocean with a constant temperature throughout its volume.

Additionally, if it is also assumed that the now “liberated” model ocean-world can radiate its body heat away — as infrared radiation into the void of space — then the entire planet with its oceanic outer shell slowly cools uniformly toward -273.16°C (-459.69°F), which is the “no heat at all” endpoint of objects in our physical Universe.

When our Earth was in its Post-Ice Age dynamic thermal equilibrium, the “heat gun” of maximal insolation to the Tropics and Subtropics warmed the oceans there; a portion of that heat was conducted and convected into the Temperate Zones and toward the Poles; where the “ice bags” of masses of ice absorbed seasonal oceanic heat by partially melting — which occurs at a constant temperature — and then refreezing. Also, the atmosphere did not trap the excess heat radiated into space. In this way cycles of warming and cooling in all of Earth’s environments were maintained in a dynamic balance that lasted for millennia.

What has been built up in the atmosphere since about 1750 is an increasing load of carbon dioxide gas and other greenhouse gases, which have the effect of throwing an increasingly heated “thermal blanket” over our planet. Now, both the heat conduction pathways and the heat convection currents, described with the use of the model, convey increasing amounts of heat energy over the course of time. As a result the masses of ice at the poles are steadily being eroded by melting despite their continuing of cycles of partial re-freezing during winter, and additional melting during summer.

Simple mathematical models can help focus the mind on the fundamental processes driving complex multi-entangled physical realities. From there, one can begin assembling more detailed well-organized quantitative descriptions of those realities, and then using those higher-order models to inform decisions regarding actions to be taken in response to those realities, if responses are necessary. This point of departure from physics plunges you into the world of psychology, sociology, economics, politics, and too often sheer madness. I leave it to another occasion to comment outside my field of expertise about all that.

Notes on the Technical Details

The cylindrically symmetric equilibrium temperature distribution for a static ocean of uniform depth, which entirely covers a spherical planet, was solved from Laplace’s equation. The temperature of the seafloor everywhere is 4°C, the surface waters at the Equator are at 30°C, and the surface waters at the poles are at -2°C. The variation of surface water temperature with respect to polar angle (latitude) is in a cosine squared distribution. Displays of the 3D surface T(r,ɵ) show isotherms down through the ocean depths at all polar angles (ɵ). The contour lines on the stream function associated with T(r,ɵ) are heat flow streamlines, the paths of the heat gradient (which are always perpendicular to the isotherms).

Bernoulli’s Theorem was applied to surface flow from the equator to the poles (no radial, nor cross-longitudinal motion) for incompressible liquid water with thermal pressure given by:


for R equal to the planetary radius to the ocean surface; Tp=-2°C; and using thermodynamic data for water between 32°F (0°C) and 100°F (37.8°C) that indicates a thermal pressure equal to 62.25kg/m-sec^2 in liquid water at 0°C; and that the density of water is essentially constant at 1000kg/m^3 (for the purposes of this model) within the temperature range of the data surveyed.

Inserting P(T°C) into the Bernoulli Theorem definition of equator-to-pole lateral (cross-latitudinal) velocity gives a formula for that velocity as a function of polar angle:



for Te=30°C, and ± for northward (in the Northern Hemisphere) or southward (in the Southern Hemisphere) surface flows.