First I will deal with the "I don't believe in Global Warming" and the "Global Warming has stopped" schools of thought.
There are temperature measurements performed over centuries that show a rising trend of temperature when plotted against time. At the places where these measurements were taken the temperature has risen. Almost everywhere that people have been recording temperatures it has been getting hotter. This is not a matter for "belief". It is indeed possible to say that "I believe Global Warming only applies to the surface of the Earth where measurements are taken (ie: much of the Earth)" or "I do not think human beings have caused Global Warming" but it is simply ignorant to say "I do not believe in Global Warming".
The UN, Intergovernmental Panel on Climate Change Fifth Assessment Report is available now. The Physical Science Basis is available at http://www.climatechange2013.org/images/report/WG1AR5_ALL_FINAL.pdf
The first graphic in this Report shows Global Warming:
It also shows that the idea that "Global Warming has stopped" is enough to make a grown scientist weep:
Global temperature is a complex system, it changes "noisily", the recent hiatus in temperature rise is entirely normal in a natural system and will not affect the long term trend. If the long term trend is linear we would expect a 1.1 to 1.6 degrees change from 1900 to 2050:
This simple extrapolation is not part of the IPCC Report - it is something anyone could estimate. These linear estimates predict 1.4 to 2.4 degrees change by the end of the century. The actual IPCC predictions based on hugely expensive computer models (called RCPn) are:
Or in other words from 1.5 to 2 degrees is the consensus estimate. However, the various models differ widely in the amount of the rise and the distribution of the rise in temperature:
The RCP 2.6 model suggests that we don't really need to worry whereas the RCP 8.5 model suggests most of the people in the world will die. Even linear extrapolation is slightly more pessimistic than the RCP 2.6 model. The RCP 2.6 model is also wildly wrong about the arctic which is already headed for RCP 8.5 levels of temperature change.
The real punchline of the report is contained in the following graph from Working Group II ( http://www.ipcc-wg2.gov/AR5/ ):
Food production is likely to decline at 1-2% per decade. Now, we could hope for better crops using GM or similar, but ultimately there is only so much yield possible from a square metre of land and advances, even if they are excellent are only going to keep production steady. But the people who run the world are determined to increase the global population by a couple of billion in the next 30 years.... In fact "Global Warming" is just an effect of "Overpopulation".
What the IPCC paper seems to have missed is that nowadays agriculture is dependent on oil. They had a glimpse of awareness in the following graphic but seemed surprised:
The consequence of this dependence is that, yes, we can probably produce more food to counteract global warming but at the cost of producing a lot more CO2......
There are temperature measurements performed over centuries that show a rising trend of temperature when plotted against time. At the places where these measurements were taken the temperature has risen. Almost everywhere that people have been recording temperatures it has been getting hotter. This is not a matter for "belief". It is indeed possible to say that "I believe Global Warming only applies to the surface of the Earth where measurements are taken (ie: much of the Earth)" or "I do not think human beings have caused Global Warming" but it is simply ignorant to say "I do not believe in Global Warming".
The UN, Intergovernmental Panel on Climate Change Fifth Assessment Report is available now. The Physical Science Basis is available at http://www.climatechange2013.org/images/report/WG1AR5_ALL_FINAL.pdf
The first graphic in this Report shows Global Warming:
It also shows that the idea that "Global Warming has stopped" is enough to make a grown scientist weep:
This simple extrapolation is not part of the IPCC Report - it is something anyone could estimate. These linear estimates predict 1.4 to 2.4 degrees change by the end of the century. The actual IPCC predictions based on hugely expensive computer models (called RCPn) are:
"Relative to the average from year 1850 to 1900, global surface temperature change by the end of the 21st century is projected to likely exceed 1.5°C for RCP4.5, RCP6.0 and RCP8.5 (high confidence). Warming is likely to exceed 2°C for RCP6.0 and RCP8.5 (high confidence), more likely than not to exceed 2°C for RCP4.5 (high confidence), but unlikely to exceed 2°C for RCP2.6 (medium confidence). Warming is unlikely to exceed 4°C for RCP2.6, RCP4.5 and RCP6.0 (high confidence) and is about as likely as not to exceed 4°C for RCP8.5 (medium confidence). {12.4}
Or in other words from 1.5 to 2 degrees is the consensus estimate. However, the various models differ widely in the amount of the rise and the distribution of the rise in temperature:
The RCP 2.6 model suggests that we don't really need to worry whereas the RCP 8.5 model suggests most of the people in the world will die. Even linear extrapolation is slightly more pessimistic than the RCP 2.6 model. The RCP 2.6 model is also wildly wrong about the arctic which is already headed for RCP 8.5 levels of temperature change.
The real punchline of the report is contained in the following graph from Working Group II ( http://www.ipcc-wg2.gov/AR5/ ):
What the IPCC paper seems to have missed is that nowadays agriculture is dependent on oil. They had a glimpse of awareness in the following graphic but seemed surprised:
The consequence of this dependence is that, yes, we can probably produce more food to counteract global warming but at the cost of producing a lot more CO2......
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