As discussed above, keeping global climate close to the Holocene range requires a long - term atmospheric CO2 level of about 350 ppm or less,
with other climate forcings similar to today's levels.
Not exact matches
In addition, a wide range of
forcing schemes designed to span the approximate range of uncertainties associated
with anthropogenic
climate forcing estimates were generated and implemented in order to assess what differences in effects exist between the «best guess» counter-anthropogenic geoengineering
forcing scheme and
other plausible schemes.
Model simulations of 20th century global warming typically use actual observed amounts of atmospheric carbon dioxide, together
with other human (for example chloroflorocarbons or CFCs) and natural (solar brightness variations, volcanic eruptions,...)
climate -
forcing factors.
Now the Robert Rauschenberg Foundation, which he set up to provide support for causes that were important to him, is joining
forces with two
other like - minded organizations to present a series of exhibitions, panel discussions and performances that will explore
climate change.
To better understand what Kilimanjaro and
other tropical glaciers are telling us about
climate change, one ultimately ought to drive a set of tropical glacier models
with GCM simulations conducted
with and without anthropogenic
forcing (greenhouse gases and sulfate aerosol).
In general, I heartily agree —
other forcings are important, even essential, for understanding observed
climate variability and, as a community, we are only just starting to get to grips
with some of the more complicated effects.
The assessment based on these results typically takes into account the number of studies, the extent to which there is consensus among studies on the significance of detection results, the extent to which there is consensus on the consistency between the observed change and the change expected from
forcing, the degree of consistency
with other types of evidence, the extent to which known uncertainties are accounted for in and between studies, and whether there might be
other physically plausible explanations for the given
climate change.
Some of them are optimal fingerprint detection studies (estimating the magnitude of fingerprints for different external
forcing factors in observations, and determining how likely such patterns could have occurred in observations by chance, and how likely they could be confused
with climate response to
other influences, using a statistically optimal metric), some of them use simpler methods, such as comparisons between data and
climate model simulations
with and without greenhouse gas increases / anthropogenic
forcing, and some are even based only on observations.
Therefore, the cost - benefit analyses regarding the mitigation of CO2 and
other greenhouse gases need to be considered along
with the
other human
climate forcings in a broader environmental context, as well as
with respect to their role in the
climate system.»
Aspects of his comment may be unwelcome to just about everyone in one way or another, but I think it is worth noting that he says that the data issues don't detract from clear evidence of a long - term warming trend and that carbon dioxide is «a major
climate forcing» (along
with many
others):
It seems that
climate has responded to the increased
forcing due to the greenhouse effect of water vapor and CO2 (+
other GHGs)
with the result that the solar
forcing is reduced to a level so that the 0.75 C / Wm ^ -2 was maintained.
Because the structure of this year's first - ever global agreement on
climate change is also voluntary —
with each country effectively trying to peer - pressure
others into greater cuts — it matters that the Obama administration is emerging as an effective negotiating
force.
I don't like Amway salesmen either, but notice I have never mentioned that because they're not trying to
force climate change legislation down our throats!!!!!!!! But you on the
other hand continuously post things that equate conservatives
with Nazi's and crap like that.
And they have influenced a much larger body of
climate scientists (and
other scientists) into going along
with them, because they are brought into this by working to fight the good fight against the war on science by the dark
forces.
On the
other side, organizations including the Environmental Defense Fund, the Union of Concerned Scientists, and the Clean Air Task
Force have argued that the new standards will offer an economic boost by encouraging investment in clean energy and efficiency, along
with desperately needed action on emissions that will help address
climate change and reduce health impacts from air pollution.
Listening to Navarro Llanos describe Bolivia's perspective, I began to understand how
climate change — if treated as a true planetary emergency akin to those rising flood waters — could become a galvanizing
force for humanity, leaving us all not just safer from extreme weather, but
with societies that are safer and fairer in all kinds of
other ways as well.
For instance, what is the usual response of a CAGW movement supporter to learning that, under their own
climate sensitivity assumptions,
other forms of geoengineering than CO2 cutbacks could neutralize the predicted warming for < = ~ 1 % the cost and
with lesser biological side - effects (such as stratospheric dispersion of micron - scale reflective dust staying suspended for months at appropriate altitude, in radiative
forcing neutralizing orders of magnitude more than its own mass in CO2)?
And through conversations
with others in the growing
climate justice movement, I began to see all kinds of ways that
climate change could become a catalyzing
force for positive change — how it could be the best argument progressives have ever had to demand the rebuilding and reviving of local economies; to reclaim our democracies from corrosive corporate influence; to block harmful new free trade deals and rewrite old ones; to invest in starving public infrastructure like mass transit and affordable housing; to take back ownership of essential services like energy and water; to remake our sick agricultural system into something much healthier; to open borders to migrants whose displacement is linked to
climate impacts; to finally respect Indigenous land rights — all of which would help to end grotesque levels of inequality within our nations and between them.
In common
with other studies of inequity in
climate change32, we used terminology from the economics literature to define «free riders» and «
forced riders» 33, recognising that a strict definition of these terms often applies only to situations where one agent's use of a resource does not directly incur a cost to another agent.
His unwillingness to debate or
force others to debate the science of
climate change
with the vocal group of «doubters» is a shame for the position of the IPCC and
other intergovernmental bodies.
Paleo evidence have indeed shown quite strong spikes in temperature anomolies which gets back to the most important point of your paper
with Judith: the extent of natural internal variability needs to be disentangled from anthropogenic and
other forcings before we can make any conclusions about the future course of
climate.
So the issues are very much broader than the trillions of taxpayer and ratepayer dollars which the states are being
forced to devote to the misguided effort to tear down fossil fuel plants and replace them
with much more expensive and much less reliable wind and solar plants which will have no measurable impact on
climate or anything else
other than the profits of the solar / wind industries.
Traditionally, only fast feedbacks have been considered (
with the
other feedbacks either ignored or treated as
forcing), which has led to estimates of the
climate sensitivity for doubled CO2 concentrations of about 3 ◦ C.
Scientists connect seawater chemistry
with climate change and evolution TORONTO, ON — Humans get most of the blame for
climate change,
with little attention paid to the contribution of
other natural
forces.
I don't have a problem
with people taking «
climate change» seriously, as long as they don't
force such behaviour on to
others.
The physical evidence for man - made global warming has never been demonstrated - evidence that many of us trained in the sciences have been waiting.When some scientists suggest that
other forces other than man - made CO2 may be involved
with the
climate, like the Sun, the clouds, the oceans, natural sources of CO2, etc., they are met
with scorn and derision.
Regarding one
other point you touched on, it's worth noting that
climate models do poorly
with ENSO and
other chaotic variations, but well
with long term temperature trends as a function of anthropogenic
forcing.
Spectral radiance emitted to space consistent
with Tyndall gas concentrations (confirms ability to calculate radiative
forcing); magnitude of Tyndall gas radiative
forcing larger than that of all
other known
forcing agents; observed temperature changes similar in magnitude to those estimated from
forcings (confirms ballpark estimates of
climate sensitivity); observed pattern of temperature changes match Tyndall gas pattern better than that of all
other known
forcing agents.
First, the complicated models that develop emissions scenarios don't seem to be necessary for
forcing the
climate models; simply specifying a value of CO2 concentration (
with the
other greenhouse gases and anthropogenic aerosol) at 2100 along
with a simple time trajectory is sufficient to
force the
climate model.
My bottom line is that while the global
climate models, when run
with added CO2 and
other greenhouse gases, show that this is a warming effect, they are inadequate tools to assess the consequences of these human
climate forcings on the regional and local scale.
[
With all the willful misinterpretation of what is meant by the use of common words, I am being
forced to clearly state that models,
climate models and
other various formulations mean «IPCC
climate models.»
In addition, the mechanisms could depend on the background state of the
climate system, and thus on
other forcings (e.g., due to well - mixed gases, Meehl et al., 2004), or interact
with each
other.
These will, among
others, examine
climate change as a function of different
forcing levels and the carbon flows associated
with various CO2 concentration levels.
But irrespective of all these details, the key point, I think, is that bottom - up, first principles modeling coupled
with observational constraints
other than the observed GMT evolution still leave room to generate a substantial spread in aerosol
forcing and
climate sensitivity.
The main reasons are that (i)
other forcing and feedback factors may co-vary in a statistically dependent way
with CO2 and can not be separated, (ii) the operation of some
climate feedbacks depends on the time scale considered, and (iii) the strength of
climate feedbacks depends on the mean
climate.
Concentrations of
other greenhouse gases, which may have co-varied
with CO2 on the multi-million-year time scale, are not known, and neither is the aerosol loading of the atmosphere or the external
forcing of the
climate changes on this time scale.
In most cases, these range from about 2 to 4.5 C per doubled CO2 within the context of our current
climate —
with a most likely value between 2 and 3 C. On the
other hand, chapter 9 describes attempts ranging far back into paleoclimatology to relate
forcings to temperature change, sometimes directly (
with all the attendant uncertainties), and more often by adjusting model parameters to determine the
climate sensitivity ranges that allow the models to best simulate data from the past — e.g., the Last Glacial Maximum (LGM).
The bottom line is that true bumps, dips, and flat times punctuate the
climate record, and need not be spurious in order to understand them to be fluctuations around a longer term trend, which for the past 100 years has been upward,
with the years since 1950 well explained mainly by GHG - mediated
forcing, plus a smaller contribution from
other factors.
The widespread change detected in temperature observations of the surface, free atmosphere and ocean, together
with consistent evidence of change in
other parts of the
climate system, strengthens the conclusion that greenhouse gas
forcing is the dominant cause of warming during the past several decades.
The groups, ranging from the [Rockefeller Brothers Fund - supported] 350.org, Food and Water Watch,
Climate Parents, Moms Clean Air Force, The Nation, Sierra Club and others, have asked DOJ to investigate what ExxonMobil knew about climate change and when the company knew it, juxtaposing that insider knowledge, exposed by both InsideClimate News and the Los Angeles Times, with the climate change denial campaign it funded both in the past and through to the present.
Climate Parents, Moms Clean Air
Force, The Nation, Sierra Club and
others, have asked DOJ to investigate what ExxonMobil knew about
climate change and when the company knew it, juxtaposing that insider knowledge, exposed by both InsideClimate News and the Los Angeles Times, with the climate change denial campaign it funded both in the past and through to the present.
climate change and when the company knew it, juxtaposing that insider knowledge, exposed by both InsideClimate News and the Los Angeles Times,
with the
climate change denial campaign it funded both in the past and through to the present.
climate change denial campaign it funded both in the past and through to the present.»
To arrive at an attribution statement for the degree of temp rise due to human GHG emissions
with such startling confidence, you MUST know
with equal confidence the contributions from all
other climate forcings operating over that period.
The most likely candidate for that climatic variable
force that comes to mind is solar variability (because I can think of no
other force that can change or reverse in a different trend often enough, and quick enough to account for the historical climatic record) and the primary and secondary effects associated
with this solar variability which I feel are a significant player in glacial / inter-glacial cycles, counter climatic trends when taken into consideration
with these factors which are, land / ocean arrangements, mean land elevation, mean magnetic field strength of the earth (magnetic excursions), the mean state of the
climate (average global temperature), the initial state of the earth's
climate (how close to interglacial - glacial threshold condition it is) the state of random terrestrial (violent volcanic eruption, or a random atmospheric circulation / oceanic pattern that feeds upon itself possibly) / extra terrestrial events (super-nova in vicinity of earth or a random impact) along
with Milankovitch Cycles.
With the considerable work you and
others (e.g. tallbloke) have done on analysis of many potential astrophysical periodic
climate forcing processes, perhaps you could shed some light on this.
In the rest of this analysis I deal
with the question of to what extent the model simulations used by Shindell can be regarded as providing reliable information about how the real
climate system responds to
forcing from aerosols, ozone and
other forcing components.
Eight Department of Energy national laboratories, including Berkeley Lab, are combining
forces with the National Center for Atmospheric Research and
other institutions in a project called Accelerated
Climate Modeling for Energy, or ACME, which is designed to accelerate the development and application of fully coupled, state - of - the - science Earth system models for scientific and energy applications.
At least two «counterfactual» ensembles will be simulated in addition to that: one
with the greenhouse gas response removed, representing the «world that might have been» without anthropogenic greenhousre gas
forcing and the
other one without some key
climate relevant aerosols in the atmosphere.
Who is to say that the effects of the polarity reversal of the Sun's magnetic field (marking Solar Cycle 24's midpoint) will not act in concert
with other natural
forces to amplify the effects of the Sun on the Earth's future
climate in ways we can not comprehend?
This scale factor was based on simulations
with an early
climate model [3,92]; comparable
forcings are found in
other models (e.g. see discussion in [93]-RRB-, but results depend on cloud representations, assumed ice albedo and
other factors; so the uncertainty is difficult to quantify.
Such abrupt state changes are well - documented for ecosystems at many scales, and can be triggered by a variety of
forcing factors — including pollution, resource extraction, deforestation, and
other land use changes —
with climate change being only one of them (Scheffer et al., 2009; Lenton et al., 2008; Barnosky et al., 2012).
Results: Spectral radiance emitted to space consistent
with Tyndall gas concentrations (confirms ability to calculate radiative
forcing); magnitude of Tyndall gas radiative
forcing larger than that of all
other known
forcing agents; observed temperature changes similar in magnitude to those estimated from
forcings (confirms ballpark estimates of
climate sensitivity); observed pattern of temperature changes match Tyndall gas pattern better than that of all
other known
forcing agents.