The press and the climate propagandists are fond of using
phrases like “highest ever recorded” or “unprecedented” in their dispatches but
the truth is the Earth has been hotter than it is today for most of its 4,500
million year history. The Tertiary period which we now are in has been the
coolest period for 300 million years - so cool that the planet is actually going
in and out of ice-ages. Even relatively recently, the world has been warmer. It
was warmer a thousand years ago during the Medieval Warming when the Vikings
were farming in Greenland and also warmer 2000 years ago during the Roman
Warming when the ancient Britons were battling Julius Caesar wearing nothing
but blue paint.
2
Okay, the planet has been warmer but
the rate of warming is faster than it’s
ever been.
This is a case of both “We don’t know that.” and “So what?” The planet has warmed and cooled at all sorts of rates over the last four billion years. There is no evidence to suggest that it has never warmed as quickly as it is now (which in fact is not that quick). In any case, the rate of warming is kind of irrelevant. It’s how much it warms that matters, not how fast. Living creatures on this planet already experience rapid changes in temperature between day and night and summer and winter, from year to year. It’s not as though plants and animals can’t cope with a rise of one degree over two centuries which is the current rate as measured by the IPCC.
This is a case of both “We don’t know that.” and “So what?” The planet has warmed and cooled at all sorts of rates over the last four billion years. There is no evidence to suggest that it has never warmed as quickly as it is now (which in fact is not that quick). In any case, the rate of warming is kind of irrelevant. It’s how much it warms that matters, not how fast. Living creatures on this planet already experience rapid changes in temperature between day and night and summer and winter, from year to year. It’s not as though plants and animals can’t cope with a rise of one degree over two centuries which is the current rate as measured by the IPCC.
3
If CO2 emissions continue
to rise they will reach a “tipping point” and the planet will experience “runaway
warming.”
There is no known instance in geological history of “runaway warming.” There has been “runaway cooling” because cooling can create a positive feedback loop through increased albedo. A fall in temperature causes ice-sheets to expand; the larger areas of ice reflect more heat back into space which cools the planet more and causes the ice sheet to expand further – etc. etc. There is no known mechanism by which warming the planet will cause more warming to occur in an endless loop.
(Note even the “runaway cooling” such as occurred in the ice ages, and the “snowball Earth” of the Cryogenic Age, eventually came to an end.)
A level of 400 ppm (parts per million) of carbon dioxide is being currently being treated as a "warning" sign by the alarmists, saying that if it keeps rising, say to 500 ppm, runaway warming could occur. It is worth remembering that when life first started on Earth, the carbon dioxide levels were at least 250,000 ppm. In other words the atmosphere was probably around a quarter carbon dioxide. (Some palaeontologists suggest that Earth's atmosphere was almost 100% carbon dioxide but that doesn't compute.) The point is, if runaway warming did not occur when CO2 levels were in the hundred thousands of parts per million, it is not likely to occur when CO2 is only 400 parts per million.
There is no known instance in geological history of “runaway warming.” There has been “runaway cooling” because cooling can create a positive feedback loop through increased albedo. A fall in temperature causes ice-sheets to expand; the larger areas of ice reflect more heat back into space which cools the planet more and causes the ice sheet to expand further – etc. etc. There is no known mechanism by which warming the planet will cause more warming to occur in an endless loop.
(Note even the “runaway cooling” such as occurred in the ice ages, and the “snowball Earth” of the Cryogenic Age, eventually came to an end.)
A level of 400 ppm (parts per million) of carbon dioxide is being currently being treated as a "warning" sign by the alarmists, saying that if it keeps rising, say to 500 ppm, runaway warming could occur. It is worth remembering that when life first started on Earth, the carbon dioxide levels were at least 250,000 ppm. In other words the atmosphere was probably around a quarter carbon dioxide. (Some palaeontologists suggest that Earth's atmosphere was almost 100% carbon dioxide but that doesn't compute.) The point is, if runaway warming did not occur when CO2 levels were in the hundred thousands of parts per million, it is not likely to occur when CO2 is only 400 parts per million.
4 What about the permafrost? If temperatures rise, the
permafrost of the Siberia and Canada will thaw and release millions of
tonnes of CO2 into the atmosphere and that will cause runaway
warming.
During the last ice age, like all the ones before it, ice-sheets covered all of Canada (the Great Lakes mark the southern boundary), almost all of Russia, Scotland, Scandinavia and the northern half of Europe. When the ice age ended, those ice sheets retreated, exposing the frozen ground underneath. Did that release a lot of CO2. Yes, in fact. We can see a spike in atmospheric CO2 levels in the ice-core samples from that time. Did that cause runaway global warming? (Remember we’re talking about an area of permafrost far greater than what exists today.) Answer: No. There is a spike in temperatures around that time but it soon drops again.
Why did the temperature restabilise? Simple. What happens after the permafrost melts? It revegetates. The vast area of land that was trapped under the ice-sheets is today covered by the great northern pine forests that provide a lot of our oxygen. The CO2 absorbed by the trees and grasses and mosses that grew vastly exceeded the amount of CO2 released in the thaw. Thus former permafrost thus becomes a huge carbon sink.
During the last ice age, like all the ones before it, ice-sheets covered all of Canada (the Great Lakes mark the southern boundary), almost all of Russia, Scotland, Scandinavia and the northern half of Europe. When the ice age ended, those ice sheets retreated, exposing the frozen ground underneath. Did that release a lot of CO2. Yes, in fact. We can see a spike in atmospheric CO2 levels in the ice-core samples from that time. Did that cause runaway global warming? (Remember we’re talking about an area of permafrost far greater than what exists today.) Answer: No. There is a spike in temperatures around that time but it soon drops again.
Why did the temperature restabilise? Simple. What happens after the permafrost melts? It revegetates. The vast area of land that was trapped under the ice-sheets is today covered by the great northern pine forests that provide a lot of our oxygen. The CO2 absorbed by the trees and grasses and mosses that grew vastly exceeded the amount of CO2 released in the thaw. Thus former permafrost thus becomes a huge carbon sink.
5
But we know that CO2
traps heat in the atmosphere and therefore if CO2 increases then
more heat must be trapped and things must warm up.
Not quite. Only partly true. The thing is this. The surface of the Earth is warmed by solar radiation: it then re-radiates energy mostly in the form of IR – Infrared radiation – into the atmosphere. Carbon Dioxide molecules absorb the IR radiation, which excites them – i.e. heats them up – and they then heat the nitrogen and oxygen around them by direct transfer of kinetic energy (conduction). So, yes, the CO2 is warmed by the radiation and it warms the air around it.
The problem is CO2 only absorbs IR radiation of specific wavelengths, the main one being around the 15 micron range. Most of the other wavelengths, the bulk of the IR radiation, simply pass through the molecules - as they do with Nitrogen and Oxygen - out into space. If you look at a graph of the Earth’s electromagnetic spectrum, as seen by a satellite, it shows a huge dip in the middle of the IR spectrum around the 15 micron level. The IR radiation on either side of the dip continues to radiate.
Now, theoretically, if you add more carbon dioxide to the atmosphere, it will absorb more radiation in that 15 micron range, except that nearly all the energy in that range is already being absorbed by the CO2 that now exists. It is possible that more CO2 will mop up some of the IR that currently escapes but once that small fragment is gone, that’s it. The CO2 cannot be warmed beyond a certain level because, unless solar radiation increases, the amount of black body radiation coming from the Earth’s surface is fixed and radiation in those specific wavelengths is limited.
Not quite. Only partly true. The thing is this. The surface of the Earth is warmed by solar radiation: it then re-radiates energy mostly in the form of IR – Infrared radiation – into the atmosphere. Carbon Dioxide molecules absorb the IR radiation, which excites them – i.e. heats them up – and they then heat the nitrogen and oxygen around them by direct transfer of kinetic energy (conduction). So, yes, the CO2 is warmed by the radiation and it warms the air around it.
The problem is CO2 only absorbs IR radiation of specific wavelengths, the main one being around the 15 micron range. Most of the other wavelengths, the bulk of the IR radiation, simply pass through the molecules - as they do with Nitrogen and Oxygen - out into space. If you look at a graph of the Earth’s electromagnetic spectrum, as seen by a satellite, it shows a huge dip in the middle of the IR spectrum around the 15 micron level. The IR radiation on either side of the dip continues to radiate.
Now, theoretically, if you add more carbon dioxide to the atmosphere, it will absorb more radiation in that 15 micron range, except that nearly all the energy in that range is already being absorbed by the CO2 that now exists. It is possible that more CO2 will mop up some of the IR that currently escapes but once that small fragment is gone, that’s it. The CO2 cannot be warmed beyond a certain level because, unless solar radiation increases, the amount of black body radiation coming from the Earth’s surface is fixed and radiation in those specific wavelengths is limited.
6
What about Venus, which has a surface temperature hot enough to melt lead?
That’s what could happen to Earth if we allow CO2 to accumulate.
The alarmists love the Venus horror story but what happens on Venus stays on Venus. For a start, Venus receives twice as much solar radiation as Earth, being 1/3 closer to the Sun. Also Venus rotates very slowly so its surface doesn’t warm and cool on a 24 hour cycle like Earth. The atmosphere on Venus is so dense that its air pressure is 90 times as much as Earth. In other words being on the surface of Venus would be like being deep in the ocean on Earth. The pressure is so great that the carbon dioxide is almost in a liquid state.
Most of all, even though sources such as Wikipedia will refer to Venus being the result a “runaway greenhouse effect”, Venus is not strictly speaking a “greenhouse” planet. Its atmosphere is not heated by radiation reflected up from its surface. It is heated directly by the Sun. The atmosphere is so dense that very little solar radiation reaches the surface. So, rather than a greenhouse, Venus is more like a house with bitumen roof.
(Interestingly, if you look at the spectrum of infrared radiation from Venus, you see the same dip around the 15 micron wavelengths. Much longwave radiation still escapes from Venus because even its vast amount of CO2 cannot capture it.)
The alarmists love the Venus horror story but what happens on Venus stays on Venus. For a start, Venus receives twice as much solar radiation as Earth, being 1/3 closer to the Sun. Also Venus rotates very slowly so its surface doesn’t warm and cool on a 24 hour cycle like Earth. The atmosphere on Venus is so dense that its air pressure is 90 times as much as Earth. In other words being on the surface of Venus would be like being deep in the ocean on Earth. The pressure is so great that the carbon dioxide is almost in a liquid state.
Most of all, even though sources such as Wikipedia will refer to Venus being the result a “runaway greenhouse effect”, Venus is not strictly speaking a “greenhouse” planet. Its atmosphere is not heated by radiation reflected up from its surface. It is heated directly by the Sun. The atmosphere is so dense that very little solar radiation reaches the surface. So, rather than a greenhouse, Venus is more like a house with bitumen roof.
(Interestingly, if you look at the spectrum of infrared radiation from Venus, you see the same dip around the 15 micron wavelengths. Much longwave radiation still escapes from Venus because even its vast amount of CO2 cannot capture it.)
7
Okay, there may not be runaway
warming but even a few degrees could melt the Antarctic ice cap and raise ocean
levels 200 metres.
The average temperature in Antarctica, (not the coldest, just the average) is -60 degrees. That’s 60 degrees below freezing. So if the planet warmed by even as much as 5o overall, Antarctica’s average temperature would still be -55o. Not really enough to melt all the ice. To substantially melt Antarctica’s ice the planet would have to warm by about 70o which would mean the oceans near the equator would be boiling like a saucepan on the stove.
The average temperature in Antarctica, (not the coldest, just the average) is -60 degrees. That’s 60 degrees below freezing. So if the planet warmed by even as much as 5o overall, Antarctica’s average temperature would still be -55o. Not really enough to melt all the ice. To substantially melt Antarctica’s ice the planet would have to warm by about 70o which would mean the oceans near the equator would be boiling like a saucepan on the stove.
8
Well, anyway, let’s agree: CO2 warms
the planet.
Yes, well it seems so, but the relationship is uncertain. Periods of high atmospheric carbon appear to be periods of higher temperatures but it is an uneven correlation. Records of CO2 and temperature over the last million years show that the high peaks of CO2 and the high peaks of temperature roughly coincide but the temperature peaks come first. As we speak – or write - scientists are trying to re-analyse their data to try and solve this anomaly (i.e. try and make the data fit the theory). It has also been a problem over the past two decades. The most recent data suggest that CO2 levels have continued to rise past the 400 ppm level, yet temperatures have flat-lined. This, of course, makes sense if you take note of the point made in paragraph 5 above that CO2 cannot absorb more IR radiation than is available.
Yes, well it seems so, but the relationship is uncertain. Periods of high atmospheric carbon appear to be periods of higher temperatures but it is an uneven correlation. Records of CO2 and temperature over the last million years show that the high peaks of CO2 and the high peaks of temperature roughly coincide but the temperature peaks come first. As we speak – or write - scientists are trying to re-analyse their data to try and solve this anomaly (i.e. try and make the data fit the theory). It has also been a problem over the past two decades. The most recent data suggest that CO2 levels have continued to rise past the 400 ppm level, yet temperatures have flat-lined. This, of course, makes sense if you take note of the point made in paragraph 5 above that CO2 cannot absorb more IR radiation than is available.
9 Surely as developing countries like India,
China and African nations start to get “westernised” and to build coal fired
power stations. CO2 emissions are going to increase dramatically and
catastrophically.
In fact, historically, most human CO2 emissions have not been from factories, cars and power plants but from people cooking their meals every day on open fires. Today there are still some 3 billion people on Earth – almost half the population - who cook on open fires or simple stoves every day. This not only produces a huge amount of CO2, it is also contributes to loss of natural habitat as forests and jungle are cut down for fuel.
The idea of building coal powered power stations in, for example, India, outrages environmentalists, but gas and electricity produce far less carbon emissions than wood-burning stoves and open fires. Firstly, electricity and gas are only used when required while wood fires tend to be kept going all day. Secondly, power stations extract energy from fuel more efficiently: more energy is extracted per tonne of fuel and less is wasted. Establishment of coal (or nuclear) based power grids in developing countries also hastens modernisation and provides the infrastructure for alternative power sources in the future.
In fact, historically, most human CO2 emissions have not been from factories, cars and power plants but from people cooking their meals every day on open fires. Today there are still some 3 billion people on Earth – almost half the population - who cook on open fires or simple stoves every day. This not only produces a huge amount of CO2, it is also contributes to loss of natural habitat as forests and jungle are cut down for fuel.
The idea of building coal powered power stations in, for example, India, outrages environmentalists, but gas and electricity produce far less carbon emissions than wood-burning stoves and open fires. Firstly, electricity and gas are only used when required while wood fires tend to be kept going all day. Secondly, power stations extract energy from fuel more efficiently: more energy is extracted per tonne of fuel and less is wasted. Establishment of coal (or nuclear) based power grids in developing countries also hastens modernisation and provides the infrastructure for alternative power sources in the future.
10
Australia is one of the world’s
highest emitters of greenhouse gases and we need to reduce our emissions.
Australia is only a high emitter if you look at the per capita – per person - emissions which put us up there with countries like the United States and the Gulf States. This high rate is not an indication of any particular recklessness or voracity on the part of individual Australians; it is just that Australia has one of the highest standards of living in the world but compared to other countries with high standards of living we have no nuclear power stations and very little hydro-electric generation. In terms of contributing to global greenhouse gas emissions, however, the critical issue is the total amount that Australians contribute to the atmosphere. If we multiply the per capita rate of about 18 tonnes of CO2 per year per person by our population we get a total of about 414,000,000 tonnes. Though seemingly large, this is about 1.3% (0.013) of the world’s total emissions.
Now, when you are talking about emitting .013 of the world’s greenhouse gases, the notion that we need to cut those emissions by, say, 20% seems a little silly. That would represent an annual reduction of .0026 (26 ten thousandths) in world emissions. By contrast China’s emissions have increased annually this century by around 2.2% . In other words, China’s emissions have tended to increase each year by more than Australia’s total output.
But there is another important consideration. Australia has around 140 million hectares of forest both native and plantation. Forests absorb around 2 tonnes of CO2 per year which means that Australia’s forests subtract about 280 million tonnes of CO2 from the atmosphere each year. We also have around 600 million hectares of grassland. Grassland absorbs a lower amount of CO2 and also emits it but in general it soaks up about half a tonne a year. So our grasslands take up around another 300 millions tonnes of carbon dioxide. Taken at these values – a total of 580 million tonnes - the carbon dioxide that is absorbed by Australia’s tree and grasses exceeds the population’s emissions. If you add in crops, gardens, spinifex and all the other plant regimes, even if you vary those absorption rates down, Australia is still a net carbon sink. On this basis, when people like Barak Obama and U.N. climate change commissioners tell Australians that we need to do more to curb emissions, we have every right to tell them to get stuffed.
Australia is only a high emitter if you look at the per capita – per person - emissions which put us up there with countries like the United States and the Gulf States. This high rate is not an indication of any particular recklessness or voracity on the part of individual Australians; it is just that Australia has one of the highest standards of living in the world but compared to other countries with high standards of living we have no nuclear power stations and very little hydro-electric generation. In terms of contributing to global greenhouse gas emissions, however, the critical issue is the total amount that Australians contribute to the atmosphere. If we multiply the per capita rate of about 18 tonnes of CO2 per year per person by our population we get a total of about 414,000,000 tonnes. Though seemingly large, this is about 1.3% (0.013) of the world’s total emissions.
Now, when you are talking about emitting .013 of the world’s greenhouse gases, the notion that we need to cut those emissions by, say, 20% seems a little silly. That would represent an annual reduction of .0026 (26 ten thousandths) in world emissions. By contrast China’s emissions have increased annually this century by around 2.2% . In other words, China’s emissions have tended to increase each year by more than Australia’s total output.
But there is another important consideration. Australia has around 140 million hectares of forest both native and plantation. Forests absorb around 2 tonnes of CO2 per year which means that Australia’s forests subtract about 280 million tonnes of CO2 from the atmosphere each year. We also have around 600 million hectares of grassland. Grassland absorbs a lower amount of CO2 and also emits it but in general it soaks up about half a tonne a year. So our grasslands take up around another 300 millions tonnes of carbon dioxide. Taken at these values – a total of 580 million tonnes - the carbon dioxide that is absorbed by Australia’s tree and grasses exceeds the population’s emissions. If you add in crops, gardens, spinifex and all the other plant regimes, even if you vary those absorption rates down, Australia is still a net carbon sink. On this basis, when people like Barak Obama and U.N. climate change commissioners tell Australians that we need to do more to curb emissions, we have every right to tell them to get stuffed.
No comments:
Post a Comment