There are some who remain skeptical about global warming. As I reported in a recent posting, "The Great Global warming Swindle", which was the title and subject of a documentary run on the British television station Channel 4, there are those who are of the opinion that climate change is not "all our fault", and that the warming of the globe is driven by other forces than the greenhouse effect, enhanced by rising levels of CO2 in the atmosphere. One theory is that the power output of the Sun varies over time, and has been offered in some quarters as an explanation for the geologic record, that temperatures and CO2 concentrations rise in spikes during the interglacial periods, with a time interval of around 100,000 years, before the Earth runs-into the next ice-age. It seems clear enough that the current "concentration" of 390 parts per million (which should strictly be defined as a mixing ratio rather than a concentration) is unprecedented, certainly for some millions of years, although there is credible debate about the Medieval Warm Period, and why that should have happened during a time when there was comparatively little CO2 being pumped into the air by humans and their activities.
The Channel 4 documentary has come under severe attack - not surprisingly, given that its message is practically heresy! - but it now transpires, and the makers of the programme have acknowledged, that some of the graphs shown were out of date, and that there had been an element of selectivity in what data were shown. Nonetheless, it is not absolutely certain that the sole underlying cause of global warming is human-induced (anthropogenic) greenhouse gas (mainly CO2) emissions, and there is clearly an underlying cycle of warming and cooling, which our actions may exacerbate.
My own fear is that the full influence of the rising CO2, which is exceeding the capacity of the planet to absorb it by about 2 - 3 ppm per year, is yet to kick-in, and the Earth might in subsequent decades become very hot indeed, resulting either in a runaway greenhouse effect, or by melting the arctic ice and diluting the dense, saline waters from the tropics switch-off the Atlantic conveyor (which includes the Gulf Stream), resulting in a North European ice-age. If the geologic record holds true in the future, we must be due another ice-age at some relatively near point, as the "width" of the present warm interglacial period is about as wide as interglacial periods have been in the past, before the climate plunges into the next 100,000 year cold-snap! My own feeling is that running out of oil and gas will hit us before global warming does, and then our CO2 emissions will inevitably be cut, once we have far less of these carbon fuels available to burn. While that might sound good to some ears, it also raises the disquieting possibility that civilization will collapse, once there is insufficient energy to maintain its integrity.
Interestingly, another piece of evidence has been gleaned which will rally the anti-global warming camp. I should really call them the "it's all our fault" skeptics. This is the news that the planet Mars is warming-up too! The evidence is from research done by planetary scientists in the US, who believe that the Red Planet has warmed by around 0.65 degrees C during the past three decades (1970's to the 1990's), and is in similar amount to the Earth's temperature rise of 0.6 degrees C during this same period. In a recent paper published in Nature, describing the research, it is suggested that the warming of the Earth could be down to natural climate variability. This view has been opposed however by Neville Nicholls, a climate scientist at Monash University in Melbourne, who said: "The paper is interesting, but it hasn't got anything to do with the question of human impact on global warming on Earth. It is not an excuse to argue that humans are not causing global warming on Earth."
The research itself was carried out by a group led by Lori Fenton of the NASA Ames Research Centre in California. They used a computer model, similar to those devised to simulate global warming on Earth, into which were added particular Martian features such as a cold "airless" (significant - no atmosphere!) surface and a southward-moving polar ice-cap, but with the contribution from the Earth's atmosphere and its oceans removed. The study also "found" (it is a simulation) that annual variation in the amount of the Sun's radiation reflected from the Martian surface contributed to the temperature rise of the planet by increasing the amount of dust blowing in the atmosphere. Apparently, over the past 30 years the dust scourged large areas of the planet's surface making it less reflective (lower albedo) , and hence more warming occurred. The outcome of this was a positive feedback loop between dust, wind, albedo and temperature. At the University of New South Wales, climate scientist Andy Pitman commented, "It's a nice piece of work, but there are no implications for Earth."
The paper in Nature is published on the eve of the second report from the fourth IPCC review, due to be released tonight. It is also noted that computer models include the effects of changes in albedo, but might there be another explanation - for example, a change in the output of the Sun, which is not included in the models? In general, computer simulations, if they do not include a particular dominant parameter in the model, will "absorb" an effect (like rising temperature) into other parameters that are included. If there is a variation in solar output, that might result in false weightings of the importance of other effects, like wind and dust? The comparable warming of Earth and Mars may be a complete coincidence, especially given the completely different characters of their atmospheres; however, the possibility that it is not is fascinating and may point to an external cause - like the Sun.
it's me, the Italian again. how are you.
I have to say, in my opinion, while it's a good idea to reduce world fossil fuel consumption and consequently CO2 emissions, I ask myself why when they talk about global warming they give a prospect saying things like (from http://en.wikipedia.org/wiki/Intergovernmental_Panel_on_Climate_Change)
"The TAR estimate for the climate sensitivity is 1.5 to 4.5 °C; and the average surface temperature is projected to increase by 1.4 to 5.8 Celsius degrees over the period 1990 to 2100, and the sea level is projected to rise by 0.1 to 0.9 metres over the same period. The wide range in predictions is based upon several different scenarios that assume different levels of future CO2 emissions. Each scenario then has a range of possible outcomes associated with it. The most optimistic outcome assumes an aggressive campaign to reduce CO2 emissions, while the most pessimistic is a "business as usual" scenario. The more realistic scenarios fall in between."
it says "1990 to 2100", but they estimate that fossil fuels are not enough to last until 2100, so it sounds a bit odd to me, i'd say as the oil era is getting to an end, possibly global warming would be the last thing to worry about. Since it's to be expected the world will "go green" eventually (in the next few decades perhaps) It's not that I'm not concerned, it's just that I don't understand the issue as it is described. Thanks
nice to hear from you - yes I am fine, thanks! Yes, there is a lot of uncertainty, and indeed practically all the oil, much of the gas, and a lot of the coal - especially if they begin to use it in coal-liquefaction technology to make artificial oil, and for all other "fossil" purposes - will have run out by then. I agree there is probably enough coal for a long time, but with the others gone, the world will become a lot "greener", whether we like it or not!
However, it might be that civilization has collapsed by then!
So, I agree, it does seem a bit bizarre to calculate the effects of current (or higher) levels of CO2 emissions until 2100, say!
It seems obvious to me that running out of oil and gas will hit us before climate change does. I agree that the levels of CO2 are increasing relentlessly, but that will stop gradually, surely. The main problem facing humans is how to survive in the post-oil age.
There seems little option but to cut energy consumption, especially for transport. We found that little nugget, didn't we, about making huge amounts of oil from algae, but that technology is untested on the large scale. If some other technology is going to come to our aid, then we surely must start installing it very soon! Otherwise we might not have enough conventional energy sources (e.g. oil) to power the transition from the status quo to the new-age!
I gave a lecture the other night on the topic in general, and the discussion was interesting. My impression is that most people don't understand exactly how huge our energy demand is and think that putting up a couple of wind turbines (to make hydrogen) is going to do the job!
Yes, I agree there's still lots of testing to be done with oil from algae. Yet I was wondering for example if it was worth to give it a try with another source considered renewable: Geothermal power. After all it's the only renewable source that so far has been tested and working on a large scale. A million households in Italy (http://en.wikipedia.org/wiki/Geothermal_power) are already relying on it and what about Iceland, the whole country is powered by it. Allow me to say, wouldn't it be a good idea to just drill a hole in correspondernce of any hot spot and draw heat from it? I know it's not that easy, and maybe in some places it's necessary to go down for many kilometres. But what about the holes dug to extract oil and coal? Only in this case we wouldn't be using any fossil fuel, but using heat that otherwise would go wasted.
Considering also that in future possibly the majority of cars could be plug-in hybrids, that I think could be a solution. Solar panels seem to take too much space, and wind power is a bit unreliable.
What do you think?
It sounds very good. I believe you have to put metal pipes down, and pass water through them to extract the heat, and the geology has to be quite stable. For example, in Switzerland, there was an underground "slippage" which fractured some pipes at an experimental geothermal site. I know that you can just put plastic pipes say 6 feet or so under the surface and that allows air to be drawn into a building "heated" to at least 5 degrees C, which offsets some of the heating/cooling costs depending on whether it is winter/summer. The scheme is an integral part of "super efficient" buildings - i.e. buildings that require only about one tenth the energy of conventional ones. Iceland is the supreme example of geothermal power, and the geology there is not that stable is it? - since it sits on the north-Atlantic ridge, where the American and European tectonic plates are pulling apart! If it can be used to great effect on the scale you say in Italy, then why not elsewhere. I believe that energy efficiency is key to surviving post-oil, and substantial renewable sources like geothermal should be exploited. The only drawback is that a large infrastructure of underground pipes (down to fairly low depths, maybe kms?!) needs to be installed. I suppose they could be run in mine-tunnels/shafts etc., which are hot! Good idea, and should be explored, I think!
Yes, I read on Wikipedia http://en.wikipedia.org/wiki/Larderello that in Larderello in Tuscany there is geothermal power plants (I'm not sure how many or if it's just one) that produce 4,8 GWh per year.They say too "However, in recent years concerns have been expressed about the sustainability of its steam supply, as a 30% drop in steam pressure levels has been recorded from the maximum levels of the 1950s."
I didnt know of the Swiss experiment, possibly the trick is to find a suitable area.
Yet I think as I say if mines are being dug and oil wells are being drilled,why not trying this way, this is free heat that otherwise would go unexploited, and if it means to drill a new hole once in a while, well let me say I think it's a lot better than other renewables, and it's tested. While I don't know of any countries running entirely on solar panels or on wind power, Iceland is already producing most of its power from geothermal power. Hydroelectrical power is again depending on the availability of water. As always my opinion is that of a person merely interested, I'm certainly not an expert in this matters, so I may be wrong.
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Thank you Mr Obama for your informed comments.
Might I also take this opportunity to congratulate you on your recent election as President of the United States of America.
I also wish you all the best of luck with sorting out the problems of the world.
Professor Chris Rhodes.
If you guys just watch this movie of the new science advisor John Holdren of president Barack Obama
Short version of his presentation: http://usclimateaction.org/userfiles/flash/Holdren.html
Thnx for your time.
Thanks for this very powerful piece of evidence. My only comment is that really curbing carbon emissions work toward a common theme, namely that we are going to run short of fossil fuels - particularly liquid fuels for transportation, e.g. oil - and we don't want to pump more CO2 into the sky for the reasons outlined in the video.
Hence using less of them aids both intentions.
We need alternatives, however, and we need them fast! But maybe there isn't enough time left to implement them before the first calamity strikes, namely running short of oil?
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