IPCC zit er naast #2

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Op dinsdag 13 november 2007 13:05 schreef Monidique het volgende:
Ahha. Nu is de 'CO2-hoax' al een complot van communisten en wetenschappers om de buitenlanders dwars te zitten. Waarmee ze dus hypocriet zijn, want ze zijn altijd zo voor buitenlanders, maar nu opeens niet meer, dus: 'CO2-hoax' = hypocriet. Duidelijk.

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Op dinsdag 13 november 2007 13:37 schreef kawotski het volgende:
als immigrant uit Afrika zit je hier volgens mij perfect als de global warming doorzet.

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Op woensdag 5 december 2007 20:25 schreef kawotski het volgende:
Ben benieuwd naar welke onbereikbare plek de volgende top wordt gehouden. Na de slecht bereikbare plekken : Zuidpool, Valencia en Bali misschien een ideetje voor Londen, Parijs of Frankfurt?

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With this issue of Physics & Society, we kick off a debate concerning one of the main conclusions of the International Panel on Climate Change (IPCC), the UN body which, together with Al Gore, recently won the Nobel Prize for its work concerning climate change research. There is a considerable presence within the scientific community of people who do not agree with the IPCC conclusion that anthropogenic CO2 emissions are very probably likely to be primarily responsible for the global warming that has occurred since the Industrial Revolution. Since the correctness or fallacy of that conclusion has immense implications for public policy and for the future of the biosphere, we thought it appropriate to present a debate within the pages of P&S concerning that conclusion.

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Op vrijdag 18 juli 2008 11:43 schreef ItaloDancer het volgende:
Precies, er zijn dus weer een paar betwetertjes die hun kont tegen de krib willen gooien, media coverage enz.
What else is new.

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Evidence is presented that the recent worldwide land warming has occurred largely in response to a worldwide warming of the oceans rather than as a direct response to increasing greenhouse gases (GHGs) over land. Atmospheric model simulations of the last half-century with prescribed observed ocean temperature changes, but without prescribed GHG changes, account for most of the land warming. The oceanic influence has occurred through hydrodynamic-radiative teleconnections, primarily by moistening and warming the air over land and increasing the downward longwave radiation at the surface. The oceans may themselves have warmed from a combination of natural and anthropogenic influences.”

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“In summary, our results emphasize the significant role of remote oceanic influences, rather than the direct local effect of anthropogenic radiative forcings, in the recent continental warming. They suggest that the recent oceanic warming has caused the continents to warm through a different set of mechanisms than usually identified with the global impacts of SST changes. It has increased the humidity of the atmosphere, altered the atmospheric vertical motion and associated cloud fields, and perturbed the longwave and shortwave radiative fluxes at the continental surface. While continuous global measurements of most of these changes are not available through the 1961-2006 period, some humidity observations are available and do show upward trends over the continents. These include near-surface observations (Dai 2006) as well as satellite radiance measurements sensitive to upper tropospheric moisture (Soden et al. 2005).”

Although not a focus of this study, the degree to which the oceans themselves have recently warmed due to increased GHG, other anthropogenic, natural solar and volcanic forcings, or internal multi-decadal climate variations is a matter of active investigation (Stott et al. 2006; Knutson et al. 2006; Pierce et al. 2006). Reliable assessments of these contributing factors depend critically on reliable estimations of natural climate variability, either from the observational record or from coupled climate model simulations without anthropogenic forcings. Several recent studies suggest that the observed SST variability may be misrepresented in the coupled models used in preparing the IPCC’s Fourth Assessment Report, with substantial errors on interannual and decadal scales (e.g., Shukla et al. 2006, DelSole, 2006; Newman 2007; Newman et al. 2008). There is a hint of an underestimation of simulated decadal SST variability even in the published IPCC Report (Hegerl et al. 2007, FAQ9.2 Figure 1). Given these and other misrepresentations of natural oceanic variability on decadal scales (e.g., Zhang and McPhaden 2006), a role for natural causes of at least some of the recent oceanic warming should not be ruled out.

Regardless of whether or not the rapid recent oceanic warming has occurred largely from anthropogenic or natural influences, our study highlights its importance in accounting for the recent observed continental warming. Perhaps the most important conclusion to be drawn from our analysis is that the recent acceleration of global warming may not be occurring in quite the manner one might have imagined. The indirect and substantial role of the oceans in causing the recent continental warming emphasizes the need to generate reliable projections of ocean temperature changes over the next century, in order to generate more reliable projections of not just the global mean temperature and precipitation changes (Barsugli et al. 2006), but also regional climate changes.”

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Op dinsdag 22 juli 2008 16:06 schreef Ared het volgende:
Dat zou in ieder geval verklaren waarom de GHG "vingerafdruk" zo nadrukkelijk afwezig is in de de atmosfeer. Vraag blijft dan wel hoe de atmosfeer de oceaan zou moeten opwarmen. Dat is als een bad vol laten lopen met koud water en dan warme lucht de badkamer in blazen en hopen dat het water warmer wordt

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Consistency Between Satellite-Derived and Modeled Estimates of the Direct Aerosol Effect
Gunnar Myhre

In the Intergovernmental Panel on Climate Change Fourth Assessment Report, the direct aerosol effect is reported to have a radiative forcing estimate of –0.5 Watt per square meter (W m–2), offsetting the warming from CO2 by almost one-third. The uncertainty, however, ranges from –0.9 to –0.1 W m–2, which is largely due to differences between estimates from global aerosol models and observation-based estimates, with the latter tending to have stronger (more negative) radiative forcing. This study demonstrates consistency between a global aerosol model and adjustment to an observation-based method, producing a global and annual mean radiative forcing that is weaker than –0.5 W m–2, with a best estimate of –0.3 W m–2. The physical explanation for the earlier discrepancy is that the relative increase in anthropogenic black carbon (absorbing aerosols) is much larger than the overall increase in the anthropogenic abundance of aerosols.

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Records of Atlantic basin tropical cyclones (TCs) since the late-19th Century
indicate a very large upward trend in storm frequency. This increase in documented TCs
has been previously interpreted as resulting from anthropogenic climate change. However,
improvements in observing and recording practices provide an alternative interpretation for
these changes: recent studies suggest that the number of potentially missed TCs is
sufficient to explain a large part of the recorded increase in TC counts. This study explores
the influence of another factor--TC duration--on observed changes in TC frequency, using
a widely-used Atlantic TC database: HURDAT. We find that the occurrence of short-lived
storms (duration two days or less) in the database has increased dramatically, from less
than one per year in the late-19th/early-20th Century to about five per year since about 2000,
while moderate to long-lived storms have increased little, if at all. Thus, the previously
documented increase in total TC frequency since the late 19th Century in the database is
primarily due to an increase in very short-lived TCs.
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While it is possible that the recorded increase in short
duration TCs represents a real climate signal, we consider it is more plausible that the
increase arises primarily from improvements in the quantity and quality of observations,
along with enhanced interpretation techniques, which have allowed National Hurricane
Center forecasters to better monitor and detect initial TC formation, and thus incorporate
increasing numbers of very short-lived systems into the TC database.