bluewave Posted May 6, 2012 Share Posted May 6, 2012 ...... Link to comment Share on other sites More sharing options...
PhillipS Posted May 6, 2012 Share Posted May 6, 2012 http://www.mpimet.mp...012GL051094.pdf [1] The very low summer extent of Arctic sea ice that has been observed in recent years is often casually interpreted as an early-warning sign of anthropogenic global warming. For examining the validity of this claim, previously IPCC model simulations have been used. Here, we focus on the available observational record to examine if this record allows us to identify either internal variability, self-acceleration, or a specific external forcing as the main driver for the observed sea-ice retreat. We find that the available observations are sufficient to virtually exclude internal variability and self- acceleration as an explanation for the observed long-term trend, clustering, and magnitude of recent sea-ice minima. Instead, the recent retreat is well described by the super- position of an externally forced linear trend and internal variability. For the externally forced trend, we find a physi- cally plausible strong correlation only with increasing atmospheric CO2 concentration. Our results hence show that the observed evolution of Arctic sea-ice extent is consistent with the claim that virtually certainly the impact of an anthropogenic climate change is observable in Arctic sea ice already today. Citation: Notz, D., and J. Marotzke (2012), Observations reveal external driver for Arctic sea-ice retreat, Geophys. Res. Lett., 39, L08502, doi:10.1029/2012GL051094. Thank you for sharing that paper. I had seen some discussion of it in other fora (?) (forums?) (take your pick, they're the same price) but this was the first time I'd read the whole paper. Their conclusions: Conclusions [32] In this contribution, we have shown that the following conclusions can be drawn from an analysis of the available observational record: [33] 1. Internal variability as estimated from pre-satellite observations cannot explain the recent retreat of Arctic sea ice. [34] 2. The observational record shows no signs of selfacceleration and hence no signs of a possible ‘tipping’. [35] 3. The satellite record is well described by a linear trend onto which internal variability is superimposed. The magnitude of this superimposed internal variability is very similar to that of the pre-satellite record. [36] 4. The most likely explanation for the linear trend during the satellite era from 1979 onwards is the almost linear increase in CO2 concentration during that period. Those people who understand the research will see this paper as corroborating mainstream AGW theories - but, sadly, those people who prefer rhetoric to research will just ignore it. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted May 6, 2012 Share Posted May 6, 2012 I think it is starting to show up in our weather forecasts and past data(analogs). the models continue to forecast very warm global surface temps. AMSU channel 5 shows 2012 near the top of the warmest years. Except ENSO is not the only driver of this and does not explain how it is this warm. snow albedo feedback is part of it, warmer global ssts. But these are not at there peaks. the sun is not the cause. Unfortunately we are reaching new heights with GHGs where direct GHG forcing is becoming more noticeable in our weather. I know that for some they have the idea that the Earth is not at peak heating. But the Earth is at peak heating because every measurement we have comes together and leaves little to no doubt. a strong nino now would likely send 2012 into 1st place. But the bottom line is that it is far to warm vs where we should be. Link to comment Share on other sites More sharing options...
Jonger Posted May 6, 2012 Share Posted May 6, 2012 I think it is starting to show up in our weather forecasts and past data(analogs). the models continue to forecast very warm global surface temps. AMSU channel 5 shows 2012 near the top of the warmest years. Except ENSO is not the only driver of this and does not explain how it is this warm. snow albedo feedback is part of it, warmer global ssts. But these are not at there peaks. the sun is not the cause. Unfortunately we are reaching new heights with GHGs where direct GHG forcing is becoming more noticeable in our weather. I know that for some they have the idea that the Earth is not at peak heating. But the Earth is at peak heating because every measurement we have comes together and leaves little to no doubt. a strong nino now would likely send 2012 into 1st place. But the bottom line is that it is far to warm vs where we should be. Where should we be? Link to comment Share on other sites More sharing options...
Vergent Posted May 8, 2012 Share Posted May 8, 2012 Where should we be? Stability is where we should be. Rapid change is bad news. Link to comment Share on other sites More sharing options...
Jonger Posted May 8, 2012 Share Posted May 8, 2012 Stability is where we should be. Rapid change is bad news. Thanks OIL! Link to comment Share on other sites More sharing options...
Jesse Posted May 8, 2012 Share Posted May 8, 2012 I think it is starting to show up in our weather forecasts and past data(analogs). the models continue to forecast very warm global surface temps. AMSU channel 5 shows 2012 near the top of the warmest years. Except ENSO is not the only driver of this and does not explain how it is this warm. snow albedo feedback is part of it, warmer global ssts. But these are not at there peaks. the sun is not the cause. Unfortunately we are reaching new heights with GHGs where direct GHG forcing is becoming more noticeable in our weather. I know that for some they have the idea that the Earth is not at peak heating. But the Earth is at peak heating because every measurement we have comes together and leaves little to no doubt. a strong nino now would likely send 2012 into 1st place. But the bottom line is that it is far to warm vs where we should be. http://www.theretheyretheir.com/ Link to comment Share on other sites More sharing options...
donsutherland1 Posted May 8, 2012 Share Posted May 8, 2012 Many thanks for the link. I'm not surprised by the findings. The Arctic is much warmer than it was during the last warm AMO cycle and its warming has continued even as the PDO has gone cold (something that didn't happen during the last warm cycle). Link to comment Share on other sites More sharing options...
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