Sentences with phrase «effects of albedo»

Present - day observational capabilities lack sufficient capacity to monitor the environmental effects of an albedo - modification deployment.

There could still be regional cooling in places like in the north Atlantic, which could slowdown melting on Greenland, and give the world an opportunity to take advantage by putting the reduction of GHGs on the front burner asap to mitigate the effects of albedo reduction and sea level rise from that source, when the heat returns.

However, the NAS report also noted that the potential effects of albedo modification remain poorly understood and quantified.

Scientists lack even the observational tools to measure the effects of albedo modification, the report states.

To make up for those shortcomings, the report called for a research program, including smaller scale field trials, whose goal «should be to improve understanding of the range of climate and other environmental effects of albedo modification, as well as understanding of unintended impacts.»

Not exact matches

Whereas carbon levels can affect warming on a global scale, the effects of increased albedo and poor evotranspiration would affect temperatures only on a regional level.

The albedo effect, when applied to Earth, is a measure of how much of the Sun's energy is reflected back into space.

A diminishing albedo in Arctic sea ice can be considered both the cause and effect of changes in sea ice.

«Scientists have talked about Arctic melting and albedo decrease for nearly 50 years,» said Ramanathan, a distinguished professor of climate and atmospheric sciences at Scripps who has previously conducted similar research on the global dimming effects of aerosols.

Another positive feedback of global warming is the albedo effect: less white summer ice means more dark open water, which absorbs more heat from the sun.

Among the most uncertain elements in climate models are the effects of aerosols and their interactions with clouds — just the things involved in albedo modification — she says.

Fires in the planet's northern regions, he said, speed permafrost melt and contribute to the albedo effect by creating dark, exposed stretches of land.

Keith adds, however, that the few existing studies suggest albedo modification could help ameliorate some effects of global warming.

While plants also absorb carbon from the air, the team found that the warming power of water vapor and the albedo effect in particular far outweigh this cooling factor.

They tend to believe that as the planet warms, low - level cloud cover will increase, thus increasing planetary albedo (overall reflectiveness of the Earth), offsetting the increased greenhouse effect and preventing a dangerous level of global warming from occurring.

Regardless of how hot the Sahara may feel when you stand in it, the difference in radiative effect between it and rainforest is in its higher albedo, reflecting more direct sunlight, the darker forests absorb more heat.

I guess I am surprised that with better understanding of the importance of water vapor feedback, sulfate aerosols, black carbon aerosols, more rapid than expected declines in sea ice and attendant decreases in albedo, effects of the deposition of soot and dust on snow and ice decreasing albedo, and a recognition of the importance of GHGs that were probably not considered 30 years ago, that the sensitivity has changed so little over time.

There are many other feedbacks, most notably the the ice - albedo effect of Arctic sea ice, which have already passed their tipping points.

What G&T are missing is the linear effect of water vapour accelerating the ice albedo effect of change in size of the sea ice sheets.

For starters, one simply can not equate the positive feedback effect of melting ice (both reduced albedo and increased water vapor) from that of leaving maximum ice to that of minimum ice where the climate is now (and is during every interglacial period).

The radiative effect of clouds on the shortwave fluxes is computed as a seasonally varying (but fixed from one year to the next) and spatially varying atmospheric albedo.

But they do at least have certain basic physical principles in their cloud representations — clouds over ice have less albedo effect than clouds over water, you don't get high clouds in regions of subsidence, stable boundary layers lead to marine stratus, etc..

In the mid-latitudes, both of these effects (albedo and water) are competing.

Although the authors caution that their results are approximations intended to guide future modeling efforts, this study provides fundamental information regarding the relative difficulty of achieving desired albedo modification effects and is an important starting point for understanding the limits of what is widely considered one of the most viable solar geoengineering techniques.

There was more ice around in the LGM and that changes the weighting of ice - albedo feedback, but also the operation of the cloud feedback since clouds over ice have different effects than clouds over water.

There are many other feedbacks, most notably the the ice - albedo effect of Arctic sea ice, which have already passed their tipping points.

In addition, since the global surface temperature records are a measure that responds to albedo changes (volcanic aerosols, cloud cover, land use, snow and ice cover) solar output, and differences in partition of various forcings into the oceans / atmosphere / land / cryosphere, teasing out just the effect of CO2 + water vapor over the short term is difficult to impossible.

I was interested not so much in the forcing effect of clouds themselves so much as the change in albedo which might result from a change in the overall extent of global cloud cover.

Calculations as to the magnitude of this effect (that is, how dust is needed to significantly decrease glacier albedo) certainly have been done, though probably not on a global basis.

Other factors would include: — albedo shifts (both from ice > water, and from increased biological activity, and from edge melt revealing more land, and from more old dust coming to the surface...); — direct effect of CO2 on ice (the former weakens the latter); — increasing, and increasingly warm, rain fall on ice; — «stuck» weather systems bringing more and more warm tropical air ever further toward the poles; — melting of sea ice shelf increasing mobility of glaciers; — sea water getting under parts of the ice sheets where the base is below sea level; — melt water lubricating the ice sheet base; — changes in ocean currents -LRB-?)

I guess I am surprised that with better understanding of the importance of water vapor feedback, sulfate aerosols, black carbon aerosols, more rapid than expected declines in sea ice and attendant decreases in albedo, effects of the deposition of soot and dust on snow and ice decreasing albedo, and a recognition of the importance of GHGs that were probably not considered 30 years ago, that the sensitivity has changed so little over time.

«By comparing the response of clouds and water vapor to ENSO forcing in nature with that in AMIP simulations by some leading climate models, an earlier evaluation of tropical cloud and water vapor feedbacks has revealed two common biases in the models: (1) an underestimate of the strength of the negative cloud albedo feedback and (2) an overestimate of the positive feedback from the greenhouse effect of water vapor.

Note also that going back to the ice ages, the glacial - interglacial temperature swing can not be explained without full water vapour feedback on top of both the ice sheet albedo and CO2 effects.

Pretty much all existing GCMs take into account changes in cloud albedo effects (though these are still characterized by a fairly high level of uncertainty).

What G&T are missing is the linear effect of water vapour accelerating the ice albedo effect of change in size of the sea ice sheets.

I think that only illustrates the bizarre use of the global average and models that in effect suggest cutting down trees would increase albedo and cool the planet.

After all the sea / ice albedo difference is large and the southern oceans are more likely to be part of an ocean mechanism for propagating the Milankovitch effect.

There's been different flavors of how this could work, either by reducing the albedo in the early Archean (e.g., Rosing et al 2010) or increasing the greenhouse effect (Rondanelli and Lindzen, 2010).

I am well aware of the cooling effect of atmospheric particulates etc (if I remember correctly isn't it properly called albedo?)

For example, the ice age — interglacial cycles that we have been locked in for the past few million years seem to be triggered by subtle changes in the earth's orbit around the sun and in its axis of rotation (the Milankovitch cycles) that then cause ice sheets to slowly build up (or melt away)... which changes the albedo (reflectance) of the earth amplifying this effect.

Eventually, when we know more about the effects of the mechanisms involved, fluctuations in cosmic rays could be incorporated in helping model cloud albedo changes.

black soot has also been found by a recent university of california study to be the direct cause of the albedo warming effect on the otherwise highly reflective and pristine white arctic ice & snow.

Your illogic is to think that this somehow would be some sort of legitimate argument that the (inverse) cause and effect relationship between albedo and global temperature established by the laws of physics is false.

Does more evaporation lead to more clouds and if so is the net effect of more clouds to increase albedo or to further increase GHE?

The resulting increased / decreased ice is amplified by «various feedbacks, including ice - albedo, dust, vegetation and, of course, the carbon cycle which amplify the direct effects of the orbital changes.»

The fraction of the light that scatters back out to space is responsible for the increased albedo and the cooling effect from sulfate aerosols.

However, simulations using the relatively straightforward «direct effect» of aerosols (the increase in albedo of the planet due to the particle brightness) do not match the inferred changes.

The bottom line is that uncertainties in the physics of aerosol effects (warming from black carbon, cooling from sulphates and nitrates, indirect effects on clouds, indirect effects on snow and ice albedo) and in the historical distributions, are really large (as acknowledged above).

«Our estimate for the mean soot effect on spectrally integrated albedos in the Arctic (1.5 %) and Northern Hemisphere land areas (3 %) yields a Northern Hemisphere forcing of 0.3 W m2 or an effective hemispheric forcing of 0.6 W m2.»

These variables include volcanic outgassing, Malankovich cycles, tectonic plate movements, solar variability, meteor impacts, comet tails, albedo, oceanic circulation, topography, a variety of hidden threshold effects, biological evolution and human technology.»