Sentences with phrase «positive feedback assumption»

I believe that warming forecasts have been substantially exaggerated (in part due to positive feedback assumptions) and that tales of current climate change trends are greatly exaggerated and based more on noting individual outlier events and not through real data on trends (see hurricanes, for example).

Not exact matches

Extremely reflective and open to feedback, Arely sets a positive tone for her cohort as she consistently challenges her own assumptions and biases.

However, they can provide both positive and negative forcing» and Ray # 252 «we understand extremely well the way greenhouse gasses [sic] like CO2 warm the planet» So here we go — Assumptions from considerations of physics: Unless CO2 could enlist water vapour to amplify its forcing it would simply be an unremarkable trace gas in the atmosphere, but — CO2 + water (vapour) = + ve feedback implying warming CO2 + water (liquid) = - ve feedback implying cooling Facts: Clouds cover half the surface of the planet.

While there is pretty strong evidence to suggest a 1.5 C warming by doubling atmospheric CO2, suggesting a +4 C by 2100 is speculative at best requiring large assumptions of positive feedbacks that have not been observed to date.

There seems to be an assumption in that thread that a positive feedback is just that — a positive feedback that keeps on forever being positive.

Assuming that scientists haven't left out anything vital, this suggests that the net effect of water - based feedbacks is positive and would amplify GHG - induced warming by more than a factor of two.Many assumptions have been made, but the historical evidence increases our confidence in model results.

So the question whether man - made warming will be catastrophic depends on the assumption of strong net positive feedbacks in the climate system.

The study claims to have measured feedback, and have found feedback to temperature changes in the natural climate system to be negative — opposite of the assumption of strong positive feedback in climate models.

Second, the feedbacks are all based on a series of assumptions that climate science will not question (water vapour, positive cloud feedback, no / tiny lapse rate change).

As you say, we have all been sold a pup because the IPCC can not admit to what the data collected these past 40 years is clearly telling us, namely that there can not be strong positive feedbacks, the assumptions underpinning that assumption must be wrong, and that Climate Sensitivity can at the very most exceed the no feedback scenario by just a smidgen.

High climate sensitivity is derived from arbitrary assumptions of amplification by positive feedback.

We don't deny warming or greenhouse gas theory, we deny the catastrophe, which we face only if the assumption of the climate being dominated by strong net positive feedback is correct.

However, given that the CAGW position doesn't rest on specific numbers, but is instead an unorganized collection of anecdotal evidence, coupled with heavily - tweaked computer models, unfounded assumptions about positive feedbacks, and a healthy imagination about possible future disasters, a lower warming number for the 20th century will simply be brushed over with claims about aerosols being stronger than previously thought, more warming still waiting in the «pipeline» or similar ad hoc «explanations» that keep the overall story alive.

The steepness of these reductions curves is somewhat controversial because any calculation of a carbon budget which determines the steepness of the the needed reduction curve must make assumptions about when positive feedbacks in the climate system will be triggered by rising temperatures, yet these controversies are reflected in giving different probabilities about the likelihood of achieving a specific warming limit.

The second is that it rebutts Dessler 2010, who used a zero - lag regression of flux derivative for clear - sky and all - sky data, under a stated assumption of no significant radiative forcing component during the period 2000 to 2010, to conclude that cloud feedback really is positive.

He argues that the current computer models which make more alarming predictions are unreliable, and based on the assumption of large positive «water vapour feedbacks».

I think you have it basically right, but at the beginning of your post you came up with and discarded the reason it is not a runaway effect: I am assuming of course that positive feedback is linear Wrong assumption!

BTW: There is no physical evidence that the assumption of a net positive feedback is correct, and much physical evidence to suggest that the real world feedbacks are net negative and will reduce the proposed direct warming effect of CO2 towards (closer too) 0.

Models amplify that warming with assumptions about positive feedback (see the blue region of model estimates in the graph below).

What they don't say is that this point on its own is responsible for half the warming projected in the models, and hence that after twenty years of trying to reconcile the models and observations it's past time they turfed the models and trashed the assumption that humidity will cause monster positive feedback.

Studies involving 28 million weather balloons, thousands of satellite recordings, 3,000 ocean buoys, temperature recordings from 50 sites in the US and a 1,000 years of temperature proxies suggest that the Global Climate Models overestimate positive feedback and are based on poor assumptions.

Second, alarmists have been peddling a second analysis, called the Mann hockey stick, which is so contradictory to these assumptions of strong positive feedback that it is amazing to me no one has called them on the carpet for it.

The real problem though is that only a few scientists, not all of them skeptics I add, have even bothered to check this vital assumption and all such checks have reported that there isn't any apparent positive feedback at all.

Lackof accurate boundary conditions, insufficient understanding of key variables i.e, air pollution and aerosols and most of all wrongheaded assumption about the existence of positive feedback.

The catastrophe comes from the assumption that there are large net positive feedbacks in the climate system that multiply a small initial warming from CO2 many times.

It is this assumption that positive feedbacks dominate over negative feedbacks that creates the catastrophe.

The assumption of net positive climate feedback is not at all settled — in fact there is as much evidence the feedback is net negative as net positive — which may be why catastrophic theory supporters seldom if ever mention this aspect of the science in the media.

Secondly, the much more solid knowledge that without assumption of positive feedback, the whole edifice of global warming will come crashing down leaving its proponents without a government grant to support their lifestyle.

Start with the all important strongly positive feedback from water vapor assumption.

What's even worse is CO2 - induced global warming's positive - feedback assumption relies on more water vapor entering the air.

Chris there is every reason to doubt this «general picture of water feedback» particularly the still yet to proven and in my IMO wrong assumption by the IPCC that water vapour is a strong positive feedback.

In fact, I have always argued that the climate models» assumptions of strong positive feedback (they assume really, really high levels) is totally unrealistic for a long - term stable system.

The point is, there is no real scientific justification in assuming a strong positive vapour feedback in the first place as it all comes down to your initial assumptions about a) natural variation, and b) aerosols, both of which are acknowledged to be too uncertain to make such assumptions.

The issue is that the excess absorption, through the focus on CO2 and the modeling assumption of a positive feedback by water, is being modeled without a clear theoretical explanation of how exactly and by what the excess absorption is being absorbed.

Based on all the studies I cited (total of 10), it is clear that the IPCC model assumption of strong net positive cloud feedback is not substantiated by the observations or the latest model studies using improved techniques.

Using the estimate of Wyant, this would point to a 2xCO2 climate sensitivity of 1.5 C (rather than 3.2 C, as estimated by IPCC using the strongly positive net feedback assumption for clouds).