The current ice age

At regular intervals polar ice caps expand, causing widespred glaciation and causing widespread devastation to the planet's ecosystems.

The current ice age has lasted 30 million years so far. Glaciation currently happens every 100,000 years on a regular cycle.

This graph illustrates the glaciation cycles:

Ten in the last million years - and they happen with great regularly.

Until recently the preferred explanation for these cycles was [Milankovitch cycles ]. Milankovitch cycles are periodic variations the Earth's orbit, caused by factors such as changes in eccentricity of the Earth's orbit, precession and changes of its axial tilt. However, this theory suffers from several problems - and recently a theory proposing that the important variations are ones which occur inside the sun has developed.

Details of this are to be found in the article Sun's fickle heart may leave us cold.

The associated article: Solar resonant diffusion waves as a driver of terrestrial climate change [PDF].

Because of the problems with the Milankovitch cycle theory, the solar theory may be preferable even if it is short on testable predictions - simply because of the "last man standing" principle.

Whatever the causes of the temperature cycles, we are currently in an interglacial period. However we are still in an ice age. If temperatues begin to drop again, large ice sheets will form. These will increase the Earth's reflectivity and reduce the absorption of solar radiation - creating positive feedback that leads to runaway cooling - and a catastrophic drop in global temperature.

During glacial periods our planet is cold, dry, and inhospitable. Winters are longer and more severe. Few forests can survive but there are plenty of glaciers and deserts. Glaciers scrape up and pulverize vast stretches of land scraping off vegetation and topsoil and completely destroying entire ecosystems. In their wake they leave altered river courses, flattened landscapes, and piles of broken rock.

An ice age is an abnormal and relatively-rare state of affairs. Details are here. Ending the ice age would return the planet to its normal state.

Ending the ice age

If humans can successfully heat up the planet - and perhaps totally melt the ice caps - the next cycle of glaciation might conceivably be avoided - and we might successfully end the current ice age.

Ice age causes

Currently we have the continent of Antarctica siting on top of one pole, and the the Arctic Ocean is almost land-locked - so circulation around both poles of the planet is restricted, preventing ice from encountering very much warmer water.

This situation looks unlikely to change any time soon - and it is difficult to imagine us being able to do much to change it. The planet is still in a configuration where it is prone to glaciation.

Action plan

Albedo

Currently the easiest way to darken an area of land is to plant trees on it - Vegetation absorbs much light from the sun, and re-radiate it as heat. Forests are more competent at this job than other kinds of vegetation.

Trees heat up the planet by making it darker, so that it absorbs more heat, and by transpiration, where water vapor is created by leaves for cooling purposes during photosynthesis. They temporarily take some carbon out of circulation - but most of it is returned to the atmosphere when their leaves fall in autumn and rot - and when the tree trunk rots it dies. This recycling of organic matter is quite efficient - and typically only a small fraction of the carbon from dead plants winds up buried in accumulating sediments and is eventually subducted.

One place to try developing forests is deserts. The main problem in those regions is lack of water - and water could be provided by irrigation projects - dams, canals and pipes.

Another place is northern wastelands. Trees have the biggest effect on albedo if they turn snow-covered ground into evergreen forests - that shrug off snow and remain dark.

Albedo effects trump greenhouse effects, in a sense: reflected radiation is more likely to carry energy away from the planet than radiation that has been absorbed and re-emitted in all directions and at low wavelengths - and in terms of molecular vibrations - as heat.

Once energy has turned from radiation into jiggling molecules, its chance to escape into space has been lost - and that's what happens when radiation hits plant leaves.

Reflections from - e.g. water droplets - give high frequency, penetrating radiation a second chance to be turned into low frequency non-penetrating infra red radiation and heat by leaves - but the importance of this effect is reduced if the radiation is likely to have hit leaves the first time it hit the surface.

In the more distant future it seems likely that we will develop floating fertiliser delivery systems - and surface-living ocean organisms will become possible. These may be capable of rolling a green carpet over large areas of seawater, if we are prepared to fertilise them. In this way, it may be possible to convert areas of ocean into a farmable surface. This would make the planet absorb more sunlight.

In order to increase the scale of the plant life on the planet, we will also need more essential minerals and nutrients. Phosphorus is an important limiting nutrient for many plants. This can be obtained by mining. More carbon, iron, copper, zinc and magnesium may also be needed - all can be obtained by mining.

Clouds - particularly high clouds - make the planet reflect sunlight back into space. Clouds are a natural planetary thermostat that hinders attempts to increase the planet's temperature: the hotter it gets, the more high clouds form, and the more radiation is sent back into space.

This thermostat doesn't work so well at low temperatures. The cooler it gets, the fewer clouds form, and the less rain there is. If this causes enough plants to die, the planetary albedo suffers, and the earth is then in danger of turning into an icy ball.

Controlling cloud seeding using microorganisms or small particles seems like a desirable skill - if we can master it.

Greenhouse effect

By exploiting this effect, we may be able to turn the planet into something more like a greenhouse - warmer and more hospitable to both plant and animal life.

The greenhouse effect results in something analogous to wrapping a warm blanket around the planet. Trapped heat results in the poles heating more than the equator - so that heat is applied to the planet in the areas that are least hospitable to life - and so need it the most.

The insulating effect means that temperature variations over time will become less extreme - meaning that living and non-living systems will have to withstand reduced stress from thermal variations.

A stabilisation of temperatures between the poles and the equator should also lead to a reduced global temperature gradient, and reduced wind levels.

On the other hand there will probably be more evaporation, precipitation - and thus more thunder storms.

More precipitation is basically good. It will help irrigate the world and allow for plant growth - and will help to reduce desertification and forest fires. However, not everyone will enjoy a more stormy planet.

Frozen wastelands

Much of the continental land mass is concentrated around the poles.

Russia, Europe, Canada, Greenland and Antarctica would all have their climate vastly improved if they were warmer. These regions contain large areas which represent potential envronments for living systems but which are currently largely uninhabited, due to adverse temperature conditions.

Run global warming scenarios backwards in time and you get a global catastrophe - where large, previously habitable areas of the planet are reduced to icy wastelands.

Here's one of the areas that will benefit from being warmer:

Most of the human population of the planet exists around the equatorial belt. Canada and Russia are largely uninhabited because their temperature is too low.

Population density Source

The equatorial region of the planet is mostly water. Oceans are mostly empty, inhospitable wastelands as far as living system go: nutrients all sink to the bottom - where there is no light - and on the surface there's nothing to eat.

This distribution of land - where the land is concentrated around the poles - is actually what causes ice ages in the first place. Polar land masses prevent warm water from equatorial regions circulating around the frozen areas, and allow ice formed over the winter to persist over the summer - and thus accumulate.

Climate stablity

When the planet is not locked in an ice age, its climate is more stable. That is because such eras are characterised by negative feedback. The cause of this negative feedback is the fact that any increases in temperature cause water to evaporate, which forms white clouds - which reflect incoming radiation back into space, which cools the planet down again.

Timescale

Objections

They point to flooding, coral bleaching, forest fires and other problems as indications that change is undesirable.

Warming the planet might have some side effects, it is true - but at least it helps avoid the devastating global catastrophe that re-glaciation would represent.

It seems to me that these folk are mostly luddites, who see the issue as a good excuse to place limits on industrialisation and growth.

You might think environmental groups would be in favour of improving the habitability of the planet by getting rid of the parts of it that are uninhabitable frozen wastelands. You might think that they might regard CO₂ as plant food - and would embrace plans to pump it into the atmosphere. However, they seem to be more interested in pictures of doe-eyed polar bear offspring, bushfires and floods.

Progress

I am optimistic about our chances. We probably have enough time to execute this plan, and - despite the protests of objectors - progress is now clearly being made.

There is an evolutionary pressure to occupy vacant ecosystems. Now that life has become more adept at mastering technology, it is in a good postition to succeed. It seems likely that living systems will use their expertise to expand out of the equatorial band and colonise the rest of the planet, increasing the planetary albedo in the process, and tipping the planet away from its current frozen state.

The likely outcome of all this is that [ocean reclamation] will take place - and most of the planet's surface will become covered with solar energy collectors - resulting in a significantly warmer planet, with fewer icy wastelands.

Success will require efforts in these areas:

• Mining - to supply the required nutrients for all the new living organisms;
• Irrigation - and other resource distribution schemes;

Accelerate Global Warming

Slow progress leaves the planet close to the edge - and means that the climate is vulnerable to developing into another glacial era.

For example, it is widely theorised that human efforts are already responsible for preventing another glacial period from starting. If humans are all that's keeping the planet from freezing, then catastrophic events - such as meteorite impacts or global warfare - may send the planet back into another glacial cycle - probably the last thing survivors will need.

Because of these risks - and because the benefits of increased global temperatures are so great - an action plan is proposed to melt the ice caps - and more rapidly increase the safety and habitability of the planet.

Questions

What about deserts? Aren't they as bad as ice sheets? Not really - deserts can be dealt with by irrigation projects. There is no planetary water shortage - but there are water distribution problems. We need to continue to work on water distribution. Though a warmer planet will cause faster evaporation of surface water, it may help this - by increasing precipitation.

Humans are not built to withstand high temperatures - what about heatstroke? Most temperature increases will be far from the equator. Currently, regions near the equator have some of the largest population densities. Consider India, for example. Humans thrive in the conditions currently there. Even if equatorial regions become less hospitable, this seems likely to be compensated for by all the gains elsewhere.

What about costal flooding? If we successfully melt the ice caps, sea levels will rise. However, this will inevitably happen gradually - over many thousands of years. There will be lots of time to get out of the way. Currently sea levels are estimated to be rising at 1.8mm per year: this is an extremely slow rate of progress. [Ocean reclamation] technology indicates what will eventually happen to much of the ocean surface.

What about the rainforests and the coral reefs? At the moment, these are confined to equatorial regions. If the planet warms up a bit, the areas which are capable of supporting this type of ecosystem will expand substantially northwards and southwards.

What about the idea that we will turn the Earth into a planet like Venus? We are too far away from the sun for that to happen for a few billion years yet.

A message to environmental groups

I do not recommend wasting your energies trying to cool the planet down. That puts you on the side of those who want to drag the planet back into the dark ages.

I do not recommend demonising carbon either. Carbon dioxide is plant fuel. Plants thrive in CO ₂-rich atmospheres, grow faster, and absorb more CO₂. Some horticulturists pump CO₂ into greenhouses to encourage plant growth. Carbon is essential to all living things. Carbon dioxide is good. Carbon sequestration would be an idiotic move.

The hysteria about global warming serves primarily to drain energy, funds and time from more important issues. As such, it is mostly a destructive force. As with other types of religous zealotry, the supporters are typically well meaning, but misguided.

Isn't the ice age already over?

Whether humanity's efforts to heat the planet will prove sufficient to end the current ice age - despite the adverse continental positions - remains to be seen.

One thing we can be pretty sure of: the costs of failing to end the ice age will dwarf any side effects of over-zealousness in attempting to prevent it.

In summary

Unless humans intervene on a dramatic scale and successfully end the current ice age, there is a significant chance that the planet will shortly be plunged into yet another period of devastating glaciation, greatly reducing the planet's habitable zone, and destroying many living things.

Once the planet enters another glaciation cycle, positive feedback effects mean that it will be very difficult to get out again. In order to avoid this fate - and to make the planet more habitable - we should work on heating up the planet now.

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