A Study of Global Climate Change over the last 250 million years.
There are a number of key events and phenomena that have defined the history of recent (the last 250 million years) climate change on Earth. Most of these events and phenomena are quite well understood, and have been well recorded by both man and nature, with various types of independent data and proxy recording matching up remarkably closely to each other, suggesting a high level of accuracy. As our understanding of history progresses, so too will our understanding of what the future holds for us.
- The last 250 million years of climate history
The last 250 million years of climate history is reasonably obvious, and scientific evidence (in the form of what is known as Paleoclimatology) from a range of fields agrees to give us a pretty good idea of what the climate has been like during this time.
This period of Earth's history is the last half of the Phanerozoic Eon, immediately following the Permian Extinction (one of the hottest periods in Earth's history), and following through the Mesozoic and later the Cenozoic eras.
This entire period (and many other equally long periods in the distant past) was hot. Much hotter than it is today.
In fact the average temperature of the globe at that time was around 22°C, as opposed to today's 13°C. That's 9°C hotter than it is today, on average, worldwide. (To put that into context, the current view is that we're in for a very tough time if the world's average temperature rises just two full degrees worldwide...)
Put another way, it was 59% hotter than it is today, at any point on the planet.
So when you're enjoying a nice comfortable morning at 24°C, back then it would have been a sweltering 38°C. And on those really hot days when you're trying to get out of the heat of the day because it's 38°C outside, back then it would have been 60.5°C!
We know this was the case because of the efforts of many decades of teams and teams of experts in a wide range of disciplines, all operating collectively under the banner of Paleoclimatology.
- What is Paleoclimatology?
Paleoclimatology is a collective name assigned to a fascinating cooperation of scientific fields, including anthropology, archeology, chemistry, physics, biology, paleontology, geology, atmospheric and oceanic sciences. These fields come together and work cooperatively to reach conclusions about the past by interpreting evidence provided by what is known as proxy data.
For example, a radioactive isotope of carbon-14 is known to decay at a specific (and constant) rate. Therefore the amount of decay seen in any particular sample is able to be used to very accurately date that item. This is known as Radiocarbon Dating.
By Radiocarbon Dating a fossil, an accurate age of that fossil is able to be determined.
By a paleontologist being able to determine whether the fossil of a plant has many or a few pores on it's surface relative to other samples of that same species, it is able to be determined whether that plant was living in a carbon dioxide rich, or oxygen rich atmosphere, and by combining the two sets of data, it is able to deduce what the level of oxygen in an atmosphere was at a particular point in earth's history, with a great level of accuracy. This is a simple example of a complex science, where many sets of proxies are compared to each other to confirm each other, thereby making a determination about a particular aspect of Earth's ancient climate more clearly understood.
- What does Paleoclimatology tell us about the climate of Earth in the last 250 million years?
Paleoclimatology tells us with a great deal of agreement about the last 250 million years, which was broken up into two main eras; the Mesozoic and later the Cenozoic eras.
The Mesozoic Era covers the dinosaurs, among other things. In a 3 million year transition between the Jurassic and Cretaceous Eras, the global climate dropped in temperature from 22°C global average to 16°C global average - still a full 3°C hotter than our current global average.
Paleoclimatogy then tells us that another huge span of hot global temperatures existed, called Cenezoic Era.
This era stretched for another 62 million years or so, and was also far hotter than it is today.
This era was followed by what is known as the Quaternary. This period is a remarkably and unusually cold period in Earth's history, where Earth oscillated in and out of not one but several ice-ages, over a period of 1.8 million years. We are in a warm part of one of these oscillations, and according to our understanding of what caused these ice-ages (primarily the presence of the Antarctic Continent allowing snow to build up and never thaw out) it is entirely plausible that another ice-age (in fact many of them) will be in our immediate future (100's, 1000's or - less likely - 10,000's of years).
- What are the Epochs and what do they mean?
The Epochs are divisions of time in Earth's geological history that allow us to study and catagorise the earth into ever more precise increments.
The Epoch we're living in at the moment is called the Holocene Epoch, which denotes the last 10,000 years or so - the time since the last ice-age ended and our ancestors were able to become less nomadic hunters and more focused on what would become modern civilisation.
- What is Paleoclimatology?
- The last 1.8 million years of climate history
The last 1.8 million years is referred to as the Quarternary, and the more "warmer" period (which is still much colder than before the Quarternary) is called the Holocene Epoch.
- What caused the ice-ages?
The ice-ages during the Quarternary are different to the other ice-ages in Earth's very deep distant past.
The earth, the sun, the oceans, the atmosphere, and the ecosphere of the Earth are all largely the same as they were during the much hotter periods of the previous 250 million years.
The one key thing that has changed is that in the last 4 million years or so the Antarctic Continent has been moved (by way of Tectonic movement).
This has resulted in the current position of the Antarctic continent. This creates a major difference in global weather patterns to when there is no continent over the pole.
As we're seeing right now, the north pole is melting. To the point where boats can sail right over the actual pole for the first time in recorded history. Polar ice cannot form very thickly over ocean, because the water is relatively warm. Therefore the ice melts during summer months, revealing more dark ocean to absorb the sun's heat, and so the process continues.
But when a continent sits over a pole, things change. Rock is much colder than ocean, and isn't as good at absorbing and retaining heat, so snow that falls on the continent doesn't tend to melt as fast, and as a result vast ice-sheets can form that never, ever melt, even in the very "hottest" months of summer. As a result the pole becomes a sort of "heat sink" where snow builds up and builds up, all the while reflecting more and more of the sun's rays back into space and it becomes a run-away effect, which can (and often has during the Quarternary) drag the entire globe into an ice-age.
- What was the time-table of the ice-ages?
The exact time-table of the ice-ages is not known, however what we consider to be a very accurate guess is that there have been many ice-age periods of growing intensity over the past 1.8 million years.
- Why are we no longer in an ice-age?
Well the truth is, we don't exactly know what causes the interglacial periods (the warm spots between ice-ages).
They're remarkably regular, and stretch over many thousands of years, so it is likely to be a combination of factors that probably include the Milankovitch cycles, which are regular changes in Earth's orbit and angle spanning tens of thousands of years. Ultimately these oscillations in Earth's angle and distance from the sun affect the amount of heat Earth recieves, and therefore have an impact on climate.
- Will there be another ice-age?
We are currently in what is known as an "interglacial period", which by its definition means "period in between glaciers"... meaning that we see no reason to not expect another ice-age will occur.
However we simply don't know enough about the many governing systems to be certain.
It would seem, however, that while the Antarctic continent is positioned over the pole and allows a persistent ice-shelf to form, that in the absence of any other factor (such as greenhouse gases, for example) that we will indeed pass in and out of ice-ages on a regular basis, geologically speaking.
- What would another ice-age mean for life on Earth?
Well essentially not a great deal... we've been through a great many ice-ages over the last 1.8 million years, and as you can see by looking out the window, life is doing just fine.
During an ice-age there is a great deal of extinction and shift in the balance of species, however as a planetary biosphere Earth survives just fine.
And during interglacials when the earth warms up a bit, life once again springs into action, busily evolving and colonising the planet.
- What caused the ice-ages?
- The last 10,000 years of climate history
- What is the Holocene Epoch?
The Holocene Epoch is the latest Epoch of the Earth - the one in which we now live.
It spans from present day back until the end of the last ice-age, around 11,400 years ago.
The Holocene Epoch marks the latest in a long string of Interglacial periods during the Quarternary, all of which are far colder than the pre-Quarternary periods of the last 250 million years.
- What has the climate been like throughout the Holocene Epoch?
The climate during the Holocene Epoch since the last ice-age has been much the same as what we see today, with a few rises and falls that have been well recorded throughout history, both by civilisations as well as nature (such as in tree ring, varves, and other proxy indicators).
- Would civilisation have arisen without the relatively warmer climate of the Holocene Epoch?
This is debateable, but it is unlikely that civilisation as we know it would have developed during the conditions of the last ice-age, for the simple reason that agriculture, farming, and even long-term habitation would have been made difficult or even impossible by marching glaciers and a strong need to hunt herds of animals rather than domesticate and farm them.
- When is the Holocene Epoch likely to end?
We are currently in the warmest point of our interglacial, around the same temperature and duration as the Eemian Interglacial.
According to the last interglacials, we will slip into another ice-age gradually over the next 10,000 - 25,000 years, sometimes with very rapid and sudden drops.
With the injection of so much greenhouse gases into our atmosphere, however, along with the melting of so much of our ice-caps (both north and south) it is unclear whether we will enter another ice-age at all. It is entirely possible that while if we free the Antarctic Continent of ice and keep it that way that our planet may even shake free of the ice-age oscillations that have been such a dominant factor of the last 1.8 million years.
- What is the Holocene Epoch?
- The last 1,000 years of climate history
The last 1,000 years of climate change are perhaps some of the most interesting, perhaps because of how directly they impact on our consciousness and society.
Most noteable events in the last 1,000 years include the Medieval Warming period (between 1000A.D. and 1450A.D.) and the Little Ice-Age (between 1450A.D. and 1850A.D.)
Also worth mentioning during this period is the Maunder Minimum, which is a well-documented period where sunspot activity was at a remarkably low level... some 0.1% what we expect to see in recent decades.
- What was the Medieval Warm Period?
The Medieval Warm Period was a curious event that (ignoring the last 30-40 years) was the hottest period of the entire Holocene Epoch since the last ice-age.
It occurred well before anything like "carbon emissions" existed, and showed a clear and gradual rise in temperatures which then fell again, leading straight into what is now known as the Little Ice-Age.
- What was the Little Ice-Age?
The Little Ice-Age was a period immediately following the Medieval Warming Period in which many climatic changes occurred that were very detrimental, and not many positives.
One of the most noteable impacts the Little Ice-Age had was that Greenland, which had been settled and tilled by the Vikings and was green and lush during the Medievel Warming Period, became so cold that the Vikings were forced to abandon it. In fact the entire sea around the area froze over, making Greenland a desolate and isolated winter wasteland.
Other effects of the Little Ice-Age included village-destroying avalanches, glacial advance, and terrible droughts.
- What was the Maunder Minimum?
The Maunder Minimum was a period where the sun was very closely observed by many independant astronomers of the time, who meticulously counted and classified the sunspot activity on the sun. The observations by these astronomers detailed not only times and dates of sunspots, but size, description, latitude and longitude, and their movements over their brief lifespans.
Thanks to the diligent work of these solar observers we have been able to determine that the period between 1450 and 1850 was a remarkably inactive time for sunspot activity... around 0.1% the activity we see at most other points in the recorded history of sunspot activity.
Interestingly this event ties very closely to the Little Ice Age, except that the tail end of the Ice-Age would seem to indicate that the Earth took around 100 years to warm back up again after solar activity returned to "normal" levels.
- What effect has industrialisation had on Climate Change?
Industrialisation, which began at roughly the end of the Little Ice-Age in 1850 with coal-fueled factories, has done one key thing that has rarely been seen by the Earth... it has pumped massive quantities of Carbon into the atmosphere in an alarmingly short amount of time.
It should be pointed out that this carbon was all at one point in the atmosphere, and was captured and stored as solid carbon fossil fuels at a distant point in the past by some of the earliest life, and since then has been circulating in and out of the biosphere, pooling gradually into "trapped" carbon in the form of oil and coal. Industrialisation has done what life up until now has been unable to do - release that carbon back into the atmosphere where the biosphere can once again use it.
In the meantime however, this carbon is acting as a greenhouse gas, trapping heat from the sun in our atmosphere, and keeping the Earth warmer than it would be without it.
This in turn has been noticed by scientists measuring the temperature over all of 40 years, and it has created alarm bells in the media that the Earth's temperature is moving away from what it was previously.
- What are the driving factors behind Climate Change today?
The driving factors behind Climate Change today are fairly well known.
They are the same factors that have always driven Climate Change throughout history (since WELL before the 250 million year snap shot we've looked at in this discussion), and they are:
- Solar Activity
- Whether the poles are oceanic or continental
- Milankovitch Cycles
- Atmospheric Green-House gases
While this will have some effect on keeping things warmer than they would otherwise have been, we should not pretend that they're out of control and could potentially lead to a run-away greenhouse effect when the Earth is still very much colder than even the cold parts of the rest of the last 250 million years before the onslaught of the ice-ages. The truth is that we don't know whether we're heading into an ice-age, staying stable, or even heading into a thermal maxima, because the amount of time we've been studying the trend is a ridiculously short amount of time to extrapolate data from and make any kind of rational prediction of any length of the future... let alone long-term.
- What was the Medieval Warm Period?
- Present Day
Currently we are in one of the warmest periods since the end of the last ice-age... with the exception of the peak of the Medieval Warming Period.
We'll know when we're there because Greenland will become green again... to the point where people can set up villages and raise sheep and crops.
However it is absolutely vital to remember that even now, in fact even during the hottest point when Greenland was green, the global average temperature is still far, far below that which it was at the cool point at the end of the Jurassic Era, and a little over half the temperature average during the rest of the last 250 million years.
We have to remember that this period of ice-ages we've been bouncing in and out of (the Quarternary) is by far the coldest point in history for the last 250 million years... well and truly the exception to the normal state of the Earth's climate.
And while you may think "yes but the ice-ages are over and it's warm now" the truth is that the ice-ages may in fact not be over, and it is far from warm, it is still only the pale first few rays of dawn after a cold winter's night.
- What are the actual repercussions of the current climate?
Let's take a moment to consider the things we take for granted about our current global climate.
- What are the pro's and con's of a warmer climate?
- The oceans will rise, displacing millions of people. However cities can be rebuilt, and the oceans can only rise to a particular height before all the water locked up in the poles is released and no more can be released. At that point retreating from the oceans will no longer be a problem... the oceans will stop their advance.
- Agricultural land will be drowned by a rising ocean. However new opportunities will present themselves - new rich warm shallow waters will provide a much higher yield of fish, and present new opportunities in the way of fish and mollusc farms.
- Precipitation will increase. As oceans warm, they'll evaporate faster, and what goes up must come down, so it will rain more.
- More disastrous storm cells. Cyclones and Hurricanes will increase in strength, causing great amounts of damage. But we're an ingenious lot. It's not hard to make things able to resist a storm - in fact it's a lot easier than building a bridge that can withstand an earthquake, and we've become quite good at that.
- New vectors for disease, such as increased mosquito breeding grounds, rats, fleas, and other diseases that can now reach temperate places that were previously too cold to reach.
- Increased heat, rain, and CO2 in the air means increased plant activity, which means greater crop yields and more fertile pastures. Agricultural boon.
- Increased areas that are habitable by predators such as Great White Sharks and Alligators.
- What are the pro's and con's of a cooler climate?
- Increased snow coverage, glacial advance, and drought will reduce agricultural yield, decreasing food supply, which will increase famine throughout the world.
- Weak populations struggling with famine will be a breeding ground for diseases.
- Cooler climate brings with it a growing ice shelf on both poles, lowering the ocean levels and exposing new land, however most of this land will be too saline to use for hundreds or even thousands of years, without human intervention to desalinate it.
- Some of the most heavily populated parts of the world become drastically altered in habitat, reducing people's ability to function as they do now under the conditions of a permanent winter... for example roads being permanent snowed out, airports being closed to blizzards, food and medical supplies being unable to be effectively moved in and out of cities, etc etc.
- What was the Fossil Fuel Industrial Revolution?
The Fossil Fuel Industrial Revolution (part of the Second Industrial Revolution of 1850) immediately followed the Steam Industrial Revolution of the early 1800's. This was where coal and oil was refined into coke and petroleum, and where steam engines were replaced with the Internal Combustion Engine, similar to the motors in our cars today.
The Fossil Fuel Industrial Revolution basically allowed us to tap into the energy stored in fossil fuels, or hydrocarbons such as oil, coal, and natural gas. This energy was stored as energy when the life forms that once lived absorbed energy from the sun to create their bodies, which subsequently died and was buried and decomposed into the massive hydrocarbon deposits that we now burn. Effectively oil is a form of chemically storing energy from the sun, which we're now using by burning it to reduce the complex hydrocarbons into their constituent parts, being H2O (water) and CO2 (Carbon Dioxide). Carbon Monoxide, actually, but it combines with Oxygen within seconds of being burned to form Carbon Dioxide.
Another way of looking at this is that millions of years ago plants absorbed energy from the sun and combined water and carbon dioxide sucked out of the atmosphere to form plant matter like leaves and branches. Animals of the time ate this vegetation, and so the carbon was passed into the animals from the plants. As time went on this carbon was retained by the biosphere of the time as plants ate animals and animals ate plants and so on, passing the carbon around and keeping it in the biosphere, while all the time plants absorbed still more CO2 from the atmosphere and converted it into complex carbon-based molecules in the form of organic matter.
This organic matter for one reason or another became buried, and decomposed into oil, coal, and natural gas deposits, never to be re-integrated into the biosphere again. Effectively this carbon had been sucked out of the atmosphere and stored, inert, in the ground, never to see the light of day again (to simplify it).
Then we came along and dug it up and burned it for its energy, putting all that carbon back into the atmosphere, and in the process rocketing ahead in industry and technology by exploiting this easy source of energy.
- Who has benefited from the output of CO2 into the atmosphere over the last 100 years?
Those that have benefited from the output of CO2 into the atmosphere are of course the coal and oil industry itself... responsible for digging up the fossil fuels, refining it, and selling it to industry world-wide. It is no secret that many billionaires have been created by the oil industry, and that much of the wealth of the middle east (among other places worldwide) has been as a result of fossil fuels.
But in addition to these usual suspects, it is important to note that everyone, to this very day, has benefited from the burning of fossil fuels.
Not only has it provided you with cheap and easy mass-transit and logistic systems (which in turn mean you can buy everything from fresh fruit and veges to beer for a fraction of the cost if we didn't have trucks and cargo ships) but it has also provided us with cheap electricity, even plastic. Without the oil industry we wouldn't have satellites that could study other planets, we wouldn't have the computer you're looking at right now, nor the internet, or cars, most of the fabrics you're wearing right now, or things as commonplace as sunglasses and CDs.
There is no question that mankind at large has benefited greatly from the countless billions of tons of plants and animals that have laid buried under the surface of our planet all these years.
- Who will benefit from the output of CO2 into the atmosphere over the next 100 years?
The output of CO2 into the atmosphere over the next 100 years will benefit any country exploiting this ready and still reasonably inexpensive source of energy.
The nation that stands to benefit the most from fossil fuels is China, which has grown in leaps and bounds in the last few decades, riding on the back of industrial and technological advancements made by the western world in the last 200 years or so.
- Who will benefit from curbing CO2 emissions in the future?
Those with the most to benefit from CO2 emissions reduction are the developed nations, for a range of complicated reasons.
But to boil it down, the western world is now industrialised, has gone through the process of burning fossil fuels, and are now looking at newer more advanced technologies such as Hydrogen combustion and direct solar energy.
China on the other hand is just catching up, however it is catching up very fast as it can benefit directly from the mistakes and successes made by western society during it's employment of fossil fuels. This means that in the immediate (our childrens' lifetime) future China will be at the exact same level of development as the western world is, at that time. The only way to stay ahead of China and the potential threat to global security this poses, is to put enough political pressure on China to slow its fossil fuel industrialisation down while western society steps into the newer technologies, thus maintaining technological superiority.
- How does climate change affect you personally?
Let's take a moment to think about how climate change over the last 40 years since the "global cooling" publications of the 1970's media has affected your life.
How has it affected your ability to work?
How has it affected your ability to purchase a major asset like a house?
How has it affected your ability to have children or visit relatives?
The truth is that in the vast majority of cases, media aside, most of us haven't even noticed the effects of Climate Change... and we're not likely to for the duration of ours lives.
- How does curbing CO2 emissions affect the rich and the poor in societies around the world?
Curbing fossil fuel industry does one key thing - it effectively "locks out" developing nations from reaching the same level of industry as currently industrialised nations. In most cases fossil fuels are a reasonably cheap and powerful bridge between domesticated animal industry, and the far more expensive technologies like Hydrogen combustion and direct solar energy. Without this bridge, the gap is basically unable to be crossed by a developing nation, trapping the nation in a state of industry similar to western society back in the 1700's... using donkeys, ox, and domestic animals to drive wheels and mills and transport people and goods.
Even putting political pressure on a nation to not use fossil fuels is enough to slow that nation's growth down, thereby increasing the gap between currently developed nations and developing nations.
- How does curbing CO2 emissions affect Earth itself?
Most people are aware that reducing CO2 emissions will provide the plant life on Earth the opportunity to once again suck the carbon back out of the atmosphere and reintroducing it back into the biosphere... where eventually it may even become buried and turn back into oil and coal for future evolutions of Earth creatures to exploit and industrialise as we have.
However even if we were able to somehow magically remove every single gram of carbon put into the atmosphere by our industry over the last 200 or so years, there are still some key factors that will (that's WILL) inevitably drive climate change.
They are: Whether there's a continental land mass or ocean at one or both of the poles, Solar Activity, and the Milankovitch Cycles that determine the Earth's exposure to Solar Radiation. Each of these factors arguably have a far stronger impact on climate change than any amount of carbon in the atmosphere could, and each of these factors are completely and utterly beyond our control... at least in the foreseeable future of our technology.
- How much impact will CO2 emissions (or the lack thereof) have on Climate Change?
So of all the factors that affect climate change (that we're aware of, excluding potential factors like radioactive decay in Earth's core and other factors we haven't yet included in our understanding of Climate Change) there is one key one that we do have some degree of control over, and which our media and public awareness is focusing heavily on at this point in history: CO2 emissions.
But just how much effect does CO2 in the atmosphere have when compared to factors like whether the poles have a continental landmass or ocean, the Milankovitch Cycles, or Solar Output? Well to begin to get an understanding of that, we need to look at history using the tools of Paleoclimatology, which spans a huge range of scientific disciplines.
Paleoclimatology tells us that in the very distant past, before the ice-ages, the amount of carbon dioxide in the atmosphere towards the end of the Miocene Epoch was in fact around the same levels as it is now, after industry has pumped all this carbon into the atmosphere.
The next epoch, called the Pliocene Epoch is a period of around 2.7 million years during which the earth very, very slowly (even in geological terms) cooled down to the point where we are now... the Quarternary... or the ice-ages.
Most climate changes throughout history have been reasonably fast, occuring over tens or hundreds of thousands of years.
The cooling during the Pliocene took 2.7 million years. That's almost 1 million years longer than the entire Quarternary to date.
So why did this cooling take place so slowly when both warming and cooling throughout history has been so very much faster than this?
The answer is because the single most powerful force in play at that time was the Antarctic Continent was moving into position over the pole, doing two key things:
- Massively altering the oceanic currents and eventually forming the Antarctic Circumpolar Current through the Drake Passage and Scotia Sea.
- Gradual build up of a persistent ice-sheet over the pole, which reflected solar radiation back into space and affected both oceanic and atmospheric temperatures in the region and ultimately around the world, acting as a huge heat sink and dragging the temperature of the globe ever colder each year as more and more ice built up and was unable to be thawed by relatively warm ocean currents melting it from underneath as we're witnessing at the north pole today.
So, to clarify, the current levels of CO2 in our atmosphere that are undeniably higher than at any point in our last 11,400 year Holocene Epoch were at the SAME LEVEL at the end of the Miocene period. Despite this the global temperatures did NOT climb.
In fact it cooled, very slowly and inexorably from a temperature 59% HOTTER than today towards what became the ice-age freeze-thaw cycle that we're at the tail end of.
Because, to put it simply, polar ice-sheets beat atmospheric carbon dioxide levels for influence over Global Climate Change.
History has proven, beyond any doubt, that a continental land mass at the south pole will completely counter-act the greenhouse effects of CO2 at the levels they're at today. Fortunately for us, Antarctica is still sitting squarely over the pole, busilly reflecting heat back out into space and remaining frigidly cold due to the ocean current running around it deflecting warm waters from the equator.
This is a fact that is likely to be the case for many millions of years to come.
As a result, if the end of the Miocene is anything to go by, it would require a lot more carbon dioxide in the atmosphere than we've already put there to prevent Antarctica from dragging us back into another ice-age as the next in the series of ice-ages that have plagued the Quarternary since Antarctica slid into position. In fact, it may not be possible to prevent at all, even if every drop of fossil fuel was burned, for the simple reason that plant life will inevitably suck it back out of the atmosphere and convert it into biomass, thus negating it's greenhouse effect.
The process of converting atmospheric greenhouse gases into biomass occurs over mere thousands over years, while the process of an ice-age spans hundreds of thousands of years... meaning that unless we kept greenhouse gases up in the air at a sufficient level to keep Earth warm during whatever forces cool the earth during an ice-age, then we would only be slowing the onslaught of the ice-age down, and not prevent it at all. Fortunately for us this is a problem that may face future generations, but is unlikely to be any real concern for us or our direct descendants.
- What are the actual repercussions of the current climate?
- The future of Climate Change
- What are likely to be the driving factors behind Climate Change in the near short-term future?
Well the near short-term future (hundreds of years) will be most heavily influenced by CO2 greenhouse gases, as all the other factors (Continental landmass over the pole, Solar activity, and Milankovitch Cycles) have in no way been altered by mankind's activity and remain in the rhythm that is demonstrated by history. These gases will trap heat and warm the globe, melting polar ice and potentially creating all sorts of problems in the immediate future, such as the shut-down of the Gulf Stream due to salinity in the northern waters being less saline from melting polar ice, which in turn would plunge Europe into an extremely frigid era for potentially hundreds of years.
Global temperatures may rise several degrees, however it is unlikely that global temperatures will reach even close to levels prior to the Pliocene (the slow steady global temperature decline in the lead-up to the period of ice-ages).
- What are likely to be the driving factors behind Climate Change in the distant short-term future?
The distant short-term future (thousands of years) will still largely be dominated by greenhouse gases, however it will be towards the end of this period that the normal cycle of ice-ages over the last 1.8 million years says that the next ice-age will begin to creep back into our climate. This will be because of Milankovitch Cycles affecting the roundness of Earth's orbit, as well as the angle of the axis of the earth compared to sun, which alters the amount of sun received at the poles during summer months.
- What are likely to be the driving factors behind Climate Change in the medium-term future?
The medium-term future (hundreds of thousands of years) will very likely see us not only pass into an ice-age but probably another interglacial and back into another ice-age. Life as we know it on this planet will very likely have changed balance by that stage, with the balance of species being very different to what it is now, and perhaps even completely new species emerging to fill niches left behind by then-extinct species of today.
It is highly unlikely that an ice-age would destroy humanity completely, however it is possible it would greatly reduce our numbers and our development... potentially reducing us to the stage we were at when the Holocene Epoch began 11,400 years ago... hunters and gatherers.
There is little doubt that regardless of our efforts with CO2 emissions, unless we can somehow counteract the effects of the Antarctic Continent trapping cold and reflecting heat at the south pole, we will fall back into another ice-age... in fact probably a continuing series of them, like clockwork, for another few million years until Antarctica eventually moves away from it's position on the pole and ocean waters are able to help keep polar ice build-up under control.
- What are likely to be the driving factors behind Climate Change in the long-term future?
Climate Change in the long-term future (millions of years) is likely to be governed by one major factor... whether Antactica is still sitting over the south pole or not.
If plate tectonics have moved the Antarctic continent off the pole without moving either the North American continent or the Asia/European Continent over the North Pole and water is free to erode polar ice in summer, then we will likely see Earth return to the extremely hot (compared to now) global temperatures that it has been at throughout the majority of history.
Contrary to what the media is telling you, this is NOT a disaster.
In fact, it's by far the normal state for Earth to be in.
The real problem here is not CO2 creating greenhouse problems for the future... we simply haven't been measuring the effects of our CO2 for long enough to extrapolate even the immediate effects, let alone the distant short-term effects.
* This document was posted after reasonably thorough research into a wide range of google-located topics and publications, using Wikipedia as a central library to describe and define key points with links. If you feel you have more accurate sources for any particular fact, please feel free to provide the fact and the source for discussion.
This essay is provided as a series of thoughts and observations, and is presented with as little bias as possible.
It is open to review, and I welcome informed discussion.
- What are likely to be the driving factors behind Climate Change in the near short-term future?