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There Will Be Consequences

Posted on 6 March 2018 by Riduna


It snows in Antarctica and has done so every day for millions of years. As it snows, air is trapped among the snowflakes. As snowflakes accumulate their combined weight increases, compressing lower layers into ice. Air trapped among the snowflakes become air bubbles in the ice and the deeper the ice, the older the air bubbles.

Drilling down through the ice has recovered ice cores containing air bubbles over 800,000 years old. Placing ice from these cores in a vacuum tube, then allowing it to melt releases ancient air. This is then analysed to find out what gases are present in the recovered air sample, an exercise which has been repeated again and again from air samples stretching back over millennia.

This air is analyzed, revealing the changing composition of Earth's atmosphere, particularly carbon dioxide (CO2) and methane (CH4) in this 800,000 year record (fig 1).


Fig 1. minimum and maximum volume of CO2 correspond to the coldest period of ice ages and thermal maxima during interglacial periods.

The record shows that during the coldest periods – ice ages – the average concentration of CO2 in the atmosphere has been found to be 175 ppm. By contrast, during thermal maxima, concentration rises to around 285 ppm. By mid 2017, CO2 concentration had reached an unprecedented 406.5 ppm, or 40% above normal.


Fig 2 shows that changes in CH4 concentration (measured in parts per billion), vary between cold (285 ppb) and warm periods (700 ppb). By 2017, CH4 concentration was estimated to have reached 1860 ppb, or 267% above the normal maximum. Graphic: EPA/Wikipedia.

Previous changes in the level of atmospheric CO2 and CH4 over the last 800,000 years have been induced by variations in Earth's orbit (called Milankovitch cycles) and have taken 10,000-15,000 years to occur. By contrast, changes above their normal maxima have occurred over the last 100-150 years – 100 times faster than the increase initiated by orbital change.

This does not mean that the environment will respond 100 times faster but a proportional response will eventually occur. Emissions of this magnitude can not be made with impunity. There will be consequences which are likely to severely affect our ability to survive as a species on this planet.

This should not come as a shock. Climate Scientists have, for decades, been warning us of the likely outcome of practices causing an increase in CO2/CH4 emissions. Their advice has been ignored and as a result, we can, at the very least, expect:

Rising Temps

The French President, Emmanuel Macron recently warned that signatories to the 2015 Paris Accord were failing to meet their commitment to reduce carbon emission and consequently the target of limiting global warming to 1.5°C or, at most, 2°C above preindustrial levels, would not be met. At the present rate of emissions average global temperature could rise more than 3°C by 2100, a prognosis indicating a doubling of CO2 concentration since the industrial revolution.

In 2017 average global temperature was almost 1°C above the preindustrial average, even though the warming effects of an El Niño were absent. Greenhouse gas emissions estimated at over 37 Gt. in 2017, accelerating at 2% per annum, makes warming of over 3°C likely. In many regions, temperatures will rise by far more than 3°C, particularly in the Arctic where mean annual temperature could increase by 9°C.

Two positive feedbacks make this a likely outcome. Firstly, as surface temperatures increase the atmosphere is able to hold more moisture in the form of water vapor – a very powerful, usually short-lived greenhouse gas. This could increase cloud cover and raise wet-bulb temperatures rendering some locations uninhabitable for some part of the year. Second, as surface temperature rises it thaws permafrost enabling resumption of biota decay, often creating water covered land surfaces and release of carbon, in the form of CH4 or, where oxidation is possible, CO2, which vent to the atmosphere.

Rising surface temperature also affects ability of oceans and vegetation to function as carbon sinks. Oceans are a major carbon sink presently absorbing about 33% of human CO2 emissions. However, as sea surface temperature warms, it induces more vigorous overturning, bringing deep carbon rich water to the surface which vents to the atmosphere until equilibrium is reached, making the oceans a net source of CO2. Rising sea surface temperature not only kills corals but also reduces ability of sea water to absorb CO2 from the atmosphere.

The capacity of the other great CO2 sink, woody vegetation, is also affected by global warming. As surface temperature increases, so does the risk of fire, often destroying large areas of forest which hitherto have been an important sink, sequestering CO2 from the atmosphere by converting it to sugars promoting woody growth. Burning of woody plants results in the release of CO2 and, at least in the short term, reduces the capacity of vegetation to absorb this gas. The result: more rapid rise of CO2 in the atmosphere and an increased rate of global warming.

Rising Seas

One of the more visible effects of global warming is the loss of snow and land based ice from glaciers. Glaciers feed rivers on which humans are heavily dependent for transport, electricity generation, irrigation and food production. All of these are threatened as glaciers recede and water flow from them initially floods, then diminishes. An even greater threat comes from loss of land based ice, particularly from the West Antarctic and Greenland ice sheets.

We know that late in the last interglacial period (the Eemian ~128 – 118 kya) global mean sea level was 6-9m higher than at present. Atmospheric greenhouse gas concentrations are now substantially higher than during the Eemian and mean global temperature will exceed the Eemian this century. Despite this, the IPCC 5th Assessment Report(see Ch.13) and reticence among climate scientists maintain the fiction that by 2100 mean sea level will have risen by less than 1m.

This is dangerous since public policy is formulated on this assurance and policy is implemented in the form of land classification and building approvals given. The result is that buildings and infrastructure are located on land which is likely to be flooded in the future with the loss of assets and disruption of services and lives. It also enables Governments to ignore what is likely to prove a very real threat to existing infrastructure on which entire economies - and populations - rely for their survival. 

Fig. 3. Projected sea level rise if mass loss from ice sheets continues to double per decade until 2100. Data based on actual annual rate of ice mass loss shows it is more than doubling per  Note relatively slow but evident rate of increase in predicted sea level rise until 2030. 

In their Paper, Hansen et al 2016, Dr James Hansen and 18 distinguished colleagues conclude that over the next 50-150 years multi meter sea level rise will occur. The time range arises from the fact that the speed with which ice sheets respond to global warming is not accurately known. If, as at present, mass loss from ice sheets continues to double per decade, this is likely to occur sooner rather than later.

Discharge of large volumes of fresh, cold water from the Greenland Ice Sheet will cool the region enough to increase polar-tropical gradients and possibly slow - but not stop - on-going loss of ice from Greenland. It is also likely to lower sea surface temperature in the North Atlantic, increasing thermal gradients between tropical and polar regions and enabling development of superstorms characteristic of the Eemian - more violent than the worst storm we have so far experienced. The argument for this is discussed by Dr Hansen in this video.

Loss of ice mass in Antarctica is discharging fresh water onto the surface of the Southern Ocean, disrupting overturning circulation and trapping relatively warm water near the ocean bed. This is likely to increase the rate of mass loss from the West Antarctic ice sheet which is particularly vulnerable to melting by warm water flowing over the seabed on which it rests.

An increase in the rate of mass loss from the West Antarctic Ice Sheet may compensate for slowing in loss expected from the Greenland ice sheet. The net result may be continued decadal doubling of ice mass loss and accelerating rates of sea level rise. This effect may not have been fully considered by the IPCC.

The immediate problem which faces us is that atmospheric concentration of greenhouse gasses are already well above those which brought about the Eemian maximum and its attendant sea level rise. As a result of ongoing emissions, it is likely that mean global temperature will exceed the Eemian, possibly by as much as 1°C (or 3°C above preindustrial) by 2100, a very dangerous increase which could result in a violent, destructive climate.

A multi-meter sea level rise of Eemian proportions, even without a violent climate, poses serious problems for our survival. It has the potential to erode coastlines by as much as 20 km., in the process inundating vast swathes of agricultural land, flooding thousands of coastal towns and cities and destroying key sections of vital infrastructure – particularly that on which transport relies. This would prove highly disruptive, effect much of the global population and potentially result in its reduction.

The future

This need not be an inevitable outcome. We have the ability to reduce carbon emissions by imposing an effective carbon tax and electrification of transport, thereby reducing combustion of fossil fuels. However, the current state of technology suggests that even if we rapidly reduce greenhouse gas emissions over the next two decades, we may be unable to slow the onset of catastrophic climate change and sea level rise much beyond the middle of next century.

Clearly we need to do more to ensure that the transition from burning fossil fuels to meet our energy needs is achieved more rapidly. Both National and International lending institutions could be required to cease lending for projects which involve burning of fossil fuels to generate electricity or meet other energy requirements. Those same institutions should be encouraged to provide increased funding, both concessional loans and grants, to accelerate construction of renewable energy generation and storage projects particularly in developing nations.

Globally all levels of government need to adopt mitigating actions which assist reduce reliance on and consumption of energy now produced by burning fossil fuels. National Governments need to adopt public policy, supported where necessary by legislation, which encourages and facilitates adoption of renewable energy as the fuel used for all forms of land transport, industrial machinery and other applications which now rely on burning fossil fuels.

We know that injection of powdered iron into the ocean promotes rapid increase of phytoplankton which are able to absorb and sequester CO2 from the atmosphere but less certain of the effects of that increase on the environment. We know that use of fast reacting silicate rock dust on farmland absorbs CO2 from the atmosphere and enhances soil fertility but its production, transport and use can release dust into the atmosphere injurious to the respiratory system of many animals – including us.

For these reasons increased investment is needed for research, development and appropriate use of technology that enhances the ability of natural sinks to absorb and sequester CO2 already in the atmosphere. International agreement on its deployment and safe use is also required to ensure that undesirable side effects, such as those noted above, are avoided.

Unless we take these or similar measures it may not be possible to avoid eventual onset of climate conditions and sea level rise inimical to our longer-term survival on this planet.

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Comments 1 to 17:

  1. I can't see business as usual lasting much longer in regards to fossil fuel use.

    I live in British Columbia in the Okanagan valley, we are already seeing the impacts of much more chaotic weather here and across this province. Last summer we had record forest fires across BC, one fire alone was over 500,000 hectares. We are also being warned once again this spring to be prepared for spring flooding as the snow packs are not behaving as they have in the past.

    And while this is happening this province has been in conflict with another who's government resents even talking about stopping a massive increase in the capacity of the Trans Mountain pipeline which carries diluted bitumen from the Athabasca tar sands to shipping terminals in the Vancouver area. One of the least sustainable of fossil fuels and if spilled one of the most polluting. If the billions of dollars required to build the new pipeline capacity which is close to 1 million barrels a day, is allowed that would require many years to see a return. We are still planning on the commercial exploitation for decades of the worst possible energy sources in this country even as governments at all levels discuss the need to mitigate climtae change.

    We here in Canada live in the bizarre state of being told we need to use more fossil fuels to fight climate change.

    The same goes for gas fracking and LNG. This is a huge issue here with the "new" provincial government approving a dam in the middle of the Montney gas formation who's only real intent can be powering an explosion of fracking across NE BC. Something the federal government also supports. While natural gas has only about 50% of the carbon intensity of coal, fracking for it also releases large amounts of methane from leakage. Making it as bad as coal as a climate change forcer.

    BC has commit to spending at least $12 billion which will likely climb to $15 billion before the Site C dam is finished. We could be spending that money on alternative energy sources across the province that would make a real difference in carbon emissions and also drive innovation in sectors that need significant stimulation to replace fossil fuels. Instead the electricty from that dam will likely go to powering gas fracking operations across the Montney gas fields. The government here has stated that no matter what its own scientific studies on the issue say, a moratorium on fracking is "unthinkable".

    We are still going in the wrong direction in regards to fossil fuels and climate change in BC and in Canada. Do not listen to claims from our politicians that they are doing something about this growing catastrophe.

    As early as 1993 the federal government was claiming that Canada was planning for a fossil fuel free future and doing our part to mitigate climate change. And investment and exploitation of fossil fuels across the nation has only grown.

    As I said at the begining, I don't think this will last much longer. We have already lost a Canadian city to climate change induced heats waves, this one in April of 2016 in Northern Alberta where temperatures reached over +20 C when usual temperatures are often -20 C in that area at that time. And came very close to losing several BC cities to fires last summer.

    At some point there will also be a political tipping point where it is simply no longer possible to deny this growing catastrophe and pretend we can base our future on fossil fuels.

    Here in Canada and BC this will mean huge stranded assets, but the alternative is changes that happen so fast and are so significant that they could possible drive our species extinct.

    Before much longer I don't think we will be talking about even carbon neutral energy models, we will be talking about carbon negative models to at least try and mitigate some of the impacts that are predicted before long and some like extreme heat waves and massive forest fires are already happening here.

    A future such as James Hansen is discussing with superstorms strong enough to hurl 1,000 ton boulders on shore is not an option. Or the loss of sea coasts through greatly increased erosion and then inundation.

    How will Asian populations feed themselves as well with areas like the Mekong and Yangtze deltas where much of the rice is grown, going under the sea or made useless to agriculture by salt water intrusion.

    Any policy that relies on fossil fuels on the decade scale should be treated in the same way we would with crimes against humanity.

    Because that is exactly what it is.

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  2. This is a well done article. The only point I would make is the possibility that things can and often are happening much faster than discussed here.

    For some reason most of science is taking the position of not wanting to worry people too much until it is too late. This is insanity.

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  3. "It snows in Antarctica....every day...." Huh?? I was under the impression it rarely snows, Antarctica is the driest continent. Most of the 'snow' is supposedly ice crystals that drift down from the stratosphere. 

    Correct me if I'm wrong.

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  4. Snowfall rates are low, but I think it reasonably likely that snow falls somewhere in Antarctica every day, especially on margins and especially on Antarctic Peninsula. Total ice discharge from Antarctica is well ahead of the estimates of mass loss so I think it is reasonable to assume the difference is snowfall.

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  5. According to this science direct article, the interior of Antarcticia receives about 2 inches (5 cm) of precipitation a year.  I presume that is 2 inches of water equivalent of snow.  Although that is not very  much precipitation, since Antarctia is so big it adds up.  This might be from the stratosphere but that is not mentioned.

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  6. Letseee heere. 

    2m of SLR could well put a brake on world population, due to the disruptions involved. There's vast capacity to produce more food, but give the choice, humans will usually create conflict over resources rather than optimizing them.   If some event breaks out which humanity is rather prone to, such as a worldwide holy war which fragments into competing holy wars, the result could be a population decline of {pick a number} %. If that number is 75 or greater, problem solved. 

    If not, the population will continue to increase until it eventually leads to more intense, more destructive wars. Then, problem solved. 

    Earth will be just fine. Humanity will continue to multiply, but perhaps for a while by a factor of less than one.  

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  7. Driving By, interesting theory but maybe, maybe not. I can't see a large drop in population anytime soon. I can't see a global religious war. People don't want global wars as much as in the past,  and even ISIS is hated by most moslems.

    Most population trends have global population peaking at 10 billion around 2100 and then either remaining static or falling but very slowly. It will only fall if family size drops below 2.1 children so this will take time to become accepted I think. Look up population growth on wikipedia.

    So it doesn't look like small population will solve the climate problem. However population growth still has to fall 'eventually', or humanity will simply run out of resources. Its about timing, and I dont think population will start falling until well into next century. That means a long time to live with climate change.

    However humaity faces so many potential risks, I do sometimes wonder if it has a long term future.

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  8. However "humanity" faces so many potential risks, I do sometimes wonder if it has a long term future. Climate change, asteroids, resource limits, mad politicians, dangerous cosmic particles, krakatoa size volcanos. Humanity exists on a knife edge.

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  9. #8
    Nigelj - you forgot the most compelling actual risk of all - unchecked population growty, which could fall under resource limits, but any biologist worth his salt will say then the collapes comes it will be very rapid.

    Still, that's no reason to ignore global warming, and other factors which surely make things worse.

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  10. The article claims that the effects of ‘business as usual’ could result in reduction of the human global population. It is likely that this will arise as a result of a combination of factors associated with climate change and SLR including:

    • Increased spread of vectors resulting in more rapid spread of diseases, exacerbated by the effects of heat-waves
    • Reduced capacity to produce and distribute food due to loss of arable land and infrastructure caused by SLR and climate severity.
    • An increase in the incidence of famine and growing inability of the international community to respond.
    • Hostilities and warfare as communities and nations compete for increasingly scare essentials of survival, particularly food and shelter.

    Very early stages of these developments are already in evidence in parts of Africa (S. Sudan warfare, Sahel drought) producing famine conditions. Reduced food crop production due to heat waves, drought and scarcity of water essential for irrigated agriculture is also evident.

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  11. The drought in Syria has been linked to both climate change and their terrible civil war.

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  12. The Science Show, broadcast by the ABC on 10 March, includes a ‘must listen to’ segment on climate change – now occurring ten times faster than in nature. It is available here

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  13. If we are going to use the term Ice Age for the icy period between the previous interglacial (the Eemian) which occured about 125,000 years ago and the present interglacial (the holocene) then we must find another term for the two to three million year period in which there have been betwen 30 and 50 cycles of glacials and interglacials (or glacial periods and interglacial periods if you like).  If you want to see why this is important, look at the BBC production Ice Age Giants to see how not using the correct terms confuses the true situation.

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  14. Riduna, great interview particularly the staged press conference. I think America has at least 3 issues flowing from this.

    1) Climate models don't fully include all possible feedbacks and tipping points and are likely to be conservative, that is the message I got.

    Imho probabilities of extremely rapid sea level rise may be small, but given the repercussions are so severe, you have to elevate this low level of risk to something of high level of concern. People in government who don't understand this need to get out of the way.

    2) Who regulates the environment, federal or state agencies? This appears to be at the core of the Trump and Republicans concerns about the issue. I acknowledge its a difficult one, and we have to avoid too much centralised power if possible, however environmental problems do not recognise borders, and this strongly suggests it has to be largely at federal level. This is just the reality of the situation, regardless of ideology.

    3) The election cycle means 4 years of climate progress, 4 years going backwards, rinse and repeat. The problem is these political systems are no longer adequate to deal with large scale, long term multi generational environmental problems. The UK has recognised this, and given over climate mitigation to an independent body, and its probably no coincidence that they have cut emissions significantly, without economic problems. Instead of attacking the EPA in America, it should be strengthened.

    4) The Republcans are very rigid on the climate issue. Sure try to convince them through explaining the Bible would promote conservation, and the security threats posed by climate change, but I don't know if this will do that much. Everyone in the country needs to be telling the Republican leadership that they are simply wrong about environmental issues. Nothing will change until they are under real pressure and are totally isolated.

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  15. nielj - ‘Imho probabilities of extremely rapid sea level rise may be small’

    This is similar to saying that the probability of sustained polar ice mass loss may be small. Among the reasons why I think this is unlikely:

    • The level of greenhouses gasses already in the atmosphere is well in excess of levels prevalent during the Eemian when SLR was 6-9 metres higher than at present.
    • Warming of the Arctic and loss of sea ice mass and extent is now occurring more rapidly than previously expected and is likely to accelerate GIS mass loss and release of greenhouse gasses from permafrost.
    • Loss of ice-shelves is promoting faster glacier discharge in Antarctica and formation of relatively warm bottom water likely to erode the West Antarctic ice sheet more rapidly than hitherto thought likely.

    Analysis by Dr Rignot of possible polar ice mass loss arising from these effects also suggests that SLR could occur rapidly and is likely to result in a multi-metre rise during the latter half of this century.

    The present rate of SLR does not suggest this. This is because loss of land-based ice has been slow - starting off at a very low rate towards the end of last century but, 20 years later accelerating at a rate sufficient to give rise for concerns about SLR over the rest of this century.

    A sea level rise in excess of 3 metres by 2100 is possible, even if deemed impossible 10 years ago and regarded as highly unlikely by many to-day. We can certainly delay this development beyond 2100 but can we prevent it? Possibly.

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  16. Riduna @15, just to be clear by rapid sea level rise I mean several metres per century. I agree its certainly very possible, but surely low probability as against high probability? 

    For example the last IPCC report had the upper limit at 1 metre so clearly by implication they think chances or probabilities of more rapid sea level rise are low.

    We dont know rates of sea level rise in the Eimean. This was a period of many thousands of years. However its certainly at the very least suggests current temperatures will lead to several metres of sea level rise, its just the speed thats in question.

    Current rates of acceleration suggest 600mm to 1000mm by end of  this century. Which is bad enough. Loss of ice shelves in Antactica could well lead to more rapid sea level rise, but the current real world data is suggesting nearer 1 metre.

    However, just in case I wasn't clear in some way, (I thought I was) even low probability of rapid sea level rise, or uncertainty about the chances,  is still extremely concerning, because the consequences of rapid sea level rise would be truly devastating. So people need to be thinking in those terms, and risk management principles and the precautionary principle need to apply. I hope I dont need to clarify this again.

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  17. A recent study, reported here, confirms that slowing of the Gulf Stream and warming of ocean water along the east coast of North America are already happening much faster than expected – and that once again Dr Hansen and his colleagues in their 2016 Paper have been proven right. These findings make a multi-metre sea level rise by 2100 accompanied by increasingly severe storms a likely outcome.

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