doesn't really say anything of the kind. As a skeptical reader (let's call him "Dad") points out, the report's overview demonstrates the continued ambiguity of the administration's position. (Italics are his comments):
Greenhouse gases are accumulating in Earth's atmosphere as a result of human activities, causing global mean surface air temperature and subsurface ocean temperature to rise. While the changes observed over the last several decades are likely due mostly to human activities, we cannot rule out that some significant part is also a reflection of natural variability.
The first sentence states that human activities ARE causing greenhouse gases to accumulate with no qualifications. The very next sentence then states that (1) "it is LIKELY due" which clearly weakens the first sentence, and (2) "We CANNOT RULE OUT natural variability" which again weakens the first sentence.
Reducing the wide range of uncertainty inherent in current model predictions will require major advances in understanding and modeling of the factors that determine atmospheric concentrations of greenhouse gases and aerosols, and the feedback processes that deter-mine the sensitivity of the climate system.
This is exactly the point I have been making that we need "advances in understanding and modeling of the factors that determine atmospheric concentrations". What could be clearer than that statement that we currently lack the knowledge to make valid predictions?
Specifically, this will involve reducing uncertainty regarding:
- the future use of fossil fuels and future emissions of methane,
- the fraction of the future fossil fuel carbon that will remain in the atmosphere and provide radiative forcing versus exchange with the oceans or net exchange with the land biosphere,
- the feedbacks in the climate system that determine both the magnitude of the change and the rate of energy uptake by the oceans,
- the impacts of climate change on regional and local levels,
- the nature and causes of the natural variability of climate and its interactions with forced changes, and
- the direct and indirect effects of the changing distributions of aerosols.
The list states that we neither know the future amount of emissions nor the basic science on how these emissions affect the climate. Besides that we got the problem licked!
Knowledge of the climate system and of projections about the future climate is derived from fundamental physics, chemistry, and observations. Data are then incorporated in global circulation models. However, model projections are limited by the paucity of data available to evaluate the ability of coupled models to simulate important aspects of climate. To overcome these limitations, it is essential to ensure the existence of a long-term observing system and to make more comprehensive regional measurements of greenhouse gases.
And besides the lack of fundamental understanding of the science, we don't even have enough data for the models!
Evidence is also emerging that black carbon aerosols (soot), which are formed by incomplete combustion, may be a significant contributor to global warming, although their relative importance is difficult to quantify at this point. These aerosols have significant negative health impacts, particularly in developing countries.
Well, we are not sure of the effect of black carbon aerosols - "its relative importance is difficult to quantify" - i.e., we DO NOT KNOW how to model it, however it is bad for our health. I agree, breathing soot is bad for our health.
While current analyses are unable to predict with confidence the timing, magnitude, or regional distribution of climate change,
This sentence states that we currently are not able to make accurate predictions of when it will happen, where it will happen, and how much it will be. Do people really think we should take any action without this knowledge?
the best scientific information indicates that if greenhouse gas concentrations continue to increase, changes are likely to occur.
"changes are likely to occur. " - What a forceful statement. I don't think any one expects otherwise. However, it would be nice it we knew what these changes are, before we cripple our economy.
The U.S. National Research Council has cautioned, however, that "because there is considerable uncertainty in current understanding of how the climate system varies naturally and reacts to emissions of greenhouse gases and aerosols, current estimates of the magnitude of future warmings should be regarded as tentative and subject to future adjustments (either upward or downward)."
"The US National research Council has cautioned that the magnitude of future warmings should be regarded as tentative and subject to future adjustments (either upward or downward)!" That is exactly what I have been trying to explain. What about this statement can't people understand? We need to do more research. We do not currently have a fundamental understanding of the problem!
Moreover, there is perhaps even greater uncertainty regarding the social, environmental, and economic consequences of changes in climate.
And if the last statement was not bad enough, there is a GREATER uncertainty as to the "social, environmental, and economic consequences of changes in climate."
I agree 100% with this assessment. Now let's take the politics out of global warming and get back to doing the necessary research to understand the problem.
Of course, this doesn't constitute proof of anything, as far as the science goes. But it does show that as far as the