I was reading Judith Curry’s Leaked IPCC report discussed in the MSM and wondered how many of our points in the sceptic view have now been adopted by the “science is settled and what the sceptics think is lunacy” brigade. It turns out that in all but one area mentioned by Judith they have moved substantially in our direction. Which makes it all the more bizarre that they INCREASE their certainty that natural variation did not cause the 20th century warming.
As such it seems that a lot of good work is going to be utterly wasted because I cannot see this report being taken seriously by any but the lunatic fringe in the media.
- Carbon Dioxide (CO2) has been increasing. In 1960 it was 0.032% of the atmosphere, today it is 0.039%.
- There has very probably been warming of average global temperatures in the last 150 years.
AR5: warming of the climate system is unequivocal.
- There is a greenhouse effect and CO2 is a greenhouse gas. The best scientific estimate of this effect (for doubling CO2) is about 1C warming.
- People think there are mechanisms that could increase warming further than the direct effect of CO2. This is not supported by the evidence.
AR5: Has a reduced predicted warming ‘likely in the range 1.5C to 4.5C… The lower limit of the assessed likely range is thus less than the 2C in the [2007 report], reflecting the evidence from new studies.’
- Current estimates of about 0.8 C temperature rise in the past 150 years are very likely too high. There is compelling evidence of malpractice, urban heating and poor instruments & siting. A figure of 0.5-0.6C warming appears more likely.
AR5: “The global combined land and ocean temperature data show an increase of about 0.8°C over the period 1901–2010.” But they admit “Rate of warming reduced from 0.2 to 0.12C per decade.” This is below their lowest previous estimate.
- Man-made sources have increased global levels of CO2, however scientific analysis shows part of the increase is natural and no one is certain how much or little of this rise is man-made.
AR5: CO2 emissions from fossil fuel combustion and cement production estimated from energy statistics have released 365 [335 to 395] PgC to the atmosphere, while deforestation and other land use change are estimated to have released 180 [100 to 260] PgC since 1750. Of these 545 [460 to 630] PgC, only 240 [230 to 250] PgC have accumulated in the atmosphere
- Water in the atmosphere is far more important than CO2 in determining global temperature.
AR5: Not an exact match but we have: ‘Climate models now include more cloud and aerosol processes, but there remains low confidence in the representation and quantification of these processes in models.’
- The harmful effects of warming have been exaggerated as shown e.g. by the absence of substantial evidence for increasing weather extremes.
AR5: “Precipitation data indicates little change in the global mean since1900, which is a revision from previous assessments.”
[Because modern equipment can measure it ..] “There have been statistically significant trends inthe number of heavy precipitation events in some regions.”
“There is low confidence in observed large-scale trends in drought”
“Tropical cyclone data provides low confidence that any reported long-term changes are robust, “
- Known benefits have been hidden. It is estimated there are more than 20,000 extra winter deaths each year in the UK and increasing fuel costs will make this worse. CO2 is essential for plant growth and increasing levels are beneficial to plants.
- Even under the worst case scenario warming, when the usual method of comparing the cost and benefit of policy is used, it is more cost effective to deal with any problems that occur than to pay to try to stop them.
- Climate proxies are not reliable. If we consider all the evidence including historical records, the evidence suggests the world was warmer during the “medieval warm period” as well as being cooler during the “little ice age”.
AR5: Now admits Medieval Climate Anomaly (950-1250) were in some regions as warm as in the late 20th Century.’
- Climate varies naturally. Most of the CO2 rise occurred in the latter half of the 20th century. If this change were man-made the global temperature change for the early and latter 20th century should be very different. They are not. This suggests a natural cause for much of the 20th century warming.
AR5: In what Prof Judith Curry describes as “incomprehensible to me” and I would describe as “delusional” AR5 states an increase in certainty from “very likely” to “extremely likely that human influence on climate caused more than half of the increase in global average surface temperature from 1951-2010.”
- In 2001 the IPCC stated with a high degree of confidence that global temperature would warm. It has not. In science a theory is not valid unless the data supports it. Climate scientists must accept this theory is not validated and acknowledge that the IPCC confidence in warming was greatly overstated.
AR5: now admits the pause and the failure of models: ‘Models do not generally reproduce the observed reduction in surface warming trend over the last 10 – 15 years.’ ‘There is medium confidence that this difference between models and observations is to a substantial degree caused by unpredictable climate variability, with possible contributions from inadequacies in the solar, volcanic, and aerosol forcings used by the models and, in some models, from too strong a response to increasing greenhouse-gas forcing.’
- We condemn the many instances of malpractice seen in climate science and those who condone them.
(Ant)arctic Ice (not mentioned in our statement)
AR5: “Most models simulate a small decreasing trend in Antarctic sea ice extent, in contrast to the small increasing trend in observations… There is low confidence in the scientific understanding of the small observed increase in Antarctic sea ice extent.”
AR5: “There is medium confidence that the modern sea ice loss and increase of sea surface temperatures in the Arctic are anomalous in the perspective of at least the last two millennia.”
“It is virtually certain that over the 20th century the mean rate of increase was between 1.4 to 2.0 mm per yr, and between 2.7 and 3.7 mm per yr since 1993.” So they are saying it is “virtually certain” that the human change of around 1-2mm rise per year will be about 10cm to 20cm per century – about the same as natural sea level change in the south of England since the last ice-age. So that makes it “virtually certain” those scare stories pushing public money to academic with stories of up to 50m rise in sea level were fraudulent.