Sentences with phrase «aerosols can warm»

While it is true that aerosols can warm and cool the climate (by absorption and reflection of solar radiation, respectively, besides influencing cloud properties), most evidence suggests that globally, cooling is dominant.

What aerosols can warm the surface so strongly in South Asia?

«Modelers defend this situation... by arguing that aerosols have cancelled [sic] much of the warming (viz Schwartz et al, 2010)... However, a recent paper (Ramanathan, 2007) points out that aerosols can warm as well as cool»

If a lack of air conditioning can not warm a room, then I fail to see how a lack of volcanic aerosols can warm the Earth.

Not exact matches

Scientists can measure how much energy greenhouse gases now add (roughly three watts per square meter), but what eludes precise definition is how much other factors — the response of clouds to warming, the cooling role of aerosols, the heat and gas absorbed by oceans, human transformation of the landscape, even the natural variability of solar strength — diminish or strengthen that effect.

On the other hand, by warming the atmosphere, aerosols can stabilize the air and protect clouds from drying out and thinning.

Aerosols are a secondary effect so they can reinforce carbon dioxide - influenced warming or slow it down.»

Indeed, conventional wisdom held that higher levels of aerosol pollution in the atmosphere should cool the earth's climate because aerosols can increase cloudiness; they not only reduce precipitation, which raises the water content in clouds, but they also increase the size of the individual water droplets, which in turn causes more warming sunlight to be reflected back into space.

Once aerosols are that high they can spread globally, destroy the ozone layer that protects us from ultraviolet radiation and exacerbate global warming, researchers warn.

The cooling effect of aerosols can partly offset global warming on a short - term basis, but many are made of organic material that comes from sources that scientists don't fully understand, said Joost de Gouw, a research physicist at NOAA's Earth System Research Laboratory in Boulder, Colo., who is unaffiliated with the studies.

Aerosols in urban air pollution and from major industries such as the Canadian tar sands are of concern to scientists because they can affect regional climate patterns and have helped to warm the Arctic.

You can, of course, argue that other factors were at work in the early 20th century warming phase, but if you want to argue that the mid-century cooling was largely due to the neutralizing effect of industrial aerosol pollutants, then you can not, as did Rodgers, claim that any part of that earlier warmup was due to the burning of fossil fuels.

1981 Hansen and others show that sulfate aerosols can significantly cool the climate, a finding that raises confidence in models showing future greenhouse warming.

Aerosols can both cool and warm depending upon a range of physical factors.

We know for a fact aerosols can affect warming so this removes any suggestion of mere coincidence.

You can even go one better — if you ignore the fact that there are negative forcings in the system as well (cheifly aerosols and land use changes), the forcing from all the warming effects is larger still (~ 2.6 W / m2), and so the implied sensitivity even smaller!

The picture is complicated because different kinds of aerosols can have different effects: black carbon or soot has warming rather than a cooling effect, for instance.

Since we would already be over 2C of warming with current CO2 levels, except for aerosols, isn't the safe amount of fossil fuels that can be burned zero?

I'm pretty sure you can get the grey version of that into a strat - cooling / trop - warming situation if you pick the strat absorbers right, but Andy is certainly right that non-grey effects play a crucial role in explaining quantitatively what is going on in the real atmosphere (that's connected with the non-grey explanation for the anomalously cold tropopause which I have in Chapter 4, and also with the reason that aerosols do not produce stratospheric cooling, and everything depends a lot on what level you are looking at).

These warming trends are consistent with the response to increasing greenhouse gases and sulphate aerosols and likely can not be explained by natural internal climate variations or the response to changes in natural external forcing (solar irradiance and volcanoes).

Greenhouse gases can be attributed to about 0.9 °C of this warming, but it has been partially offset by about 0.3 °C cooling from human aerosol emissions.

Choices regarding emissions of other warming agents, such as methane, black carbon on ice / snow, and aerosols, can affect global warming over coming decades but have little effect on longer - term warming of the Earth over centuries and millennia.

Though all available data makes clear that stratospheric aerosol geoengineering (SAG) can and does cool large regions temporarily, it comes at the cost of a worsened overall long term warming to the planet.

But the latest study suggests that aerosols can be responsible for regional warming.

So Nielsen - Gammon is correct to note that some of the slowed surface temperature warming over the past decade can be attributed to La Niña, although there have been other influences at play as well, such as human aerosol emissions.

«Observational analyses have shown the width of the tropical belt increasing in recent decades as the world has warmed... we use a climate model with detailed aerosol physics to show that increases in heterogeneous warming agents — including black carbon aerosols and tropospheric ozone — are noticeably better than greenhouse gases at driving expansion, and can account for the observed summertime maximum in tropical expansion.

So now volcanoes decide... Even if Asia will reduce «anthropogenic influences» of sulfur aerosols, nothing we gain... We can not «hope» that abruptly we have a «volcanic silence» and anthropogenic GHGs «will triumph»... An aerosol «the end» of global warming?

Thus, aerosol pollution can either warm or cool the climate, depending on its chemistry, which in turn depends on the activity responsible for the pollution.

Meanwhile, «large majorities incorrectly think that the hole in the ozone layer and aerosol spray cans contribute to global warming, leading many to incorrectly conclude that banning aerosol spray cans or stopping rockets from punching holes in the ozone layer are viable solutions.»

Two problems with that: warming is not occurring, and they can't determine the effect of the volcanic dust called aerosols.

The reason greenhouse gases can be (and probably are) responsible for more than 100 % of the observed warming is that other factors (mainly human aerosol pollution) have caused cooling at the same time.

Anomalies in the volcanic - aerosol induced global radiative heating distribution can force significant changes in atmospheric circulation, for example, perturbing the equator - to - pole heating gradient (Stenchikov et al., 2002; Ramaswamy et al., 2006a; see Section 9.2) and forcing a positive phase of the Arctic Oscillation that in turn causes a counterintuitive boreal winter warming at middle and high latitudes over Eurasia and North America (Perlwitz and Graf, 2001; Stenchikov et al., 2002, 2004, 2006; Shindell et al., 2003b, 2004; Perlwitz and Harnik, 2003; Rind et al., 2005; Miller et al., 2006).

suggests that aerosols can have either a cooling or warming effect depending on their altitude.

Even the «fingerprint» studies of the cause of global temperature change since 1850 follow a rather similar pattern: leave out half the natural variables, make unproven assumptions about aerosols etc. and you can soon fail to find any other explanation for warming that our old pal of molecular weight 44.

If warming prior to 1960 is 0.5 or greater, pretty much a given with the tropical reconstruction, Solar, aerosols, land use etc. can have have more impact than CO2 equivalent gases so your Half or complete baked explanation is going to need dLOD, fair dust and unicorns to get all the «consensus» players on the same page.

You can always try to use the magnitude of the warming over the past century itself to constrain cloud feedback, but this gets convolved with estimates of aerosol forcing and internal variability.

Based on Monte Carlo simulations and considering experimental designs with a fixed budget for the number of simulations that modeling centers can perform, the most accurate estimate of historical greenhouse gas — induced warming is obtained with a design using a combination of all - forcings, natural forcings — only, and aerosol forcing — only simulations.

However — a group of scientists of the US Department of Energy Pacific Northwest National Laboratory, the University of Maryland and the Hebrew University of Jerusalem now say that aerosol pollution does not necessarily lead to (low - lying) stratus clouds one would appreciate for climatic cooling, but that it can also be a factor in the creation of thunderstorm clouds, clouds that have a complicated climate effect, but that are suspected of being net warmers.

Sure, there are issues with time delays and the possibility of some aerosol cooling to offset some of the warming, but none of these can even come close to closing a gap between 1F and 4F.

The warming in Western Europe since about 1995 can be related to an increase of about +1 °C of the surface temperature of the North Atlantic — following an equivalent cooling over 1970 - 1995 - and an increase of the insolation with less aerosols.

Several climate scientists will attribute more than 100 % of the warming to CO2 — they can due this if the man - made reflective aerosols and ozone are canceling out a portion of the CO2 influence.

The control knob for climate change is the amount of dimming sulfur dioxide aerosol emissions in the atmosphere — the fewer there are, the warmer it gets — and we are reducing them as fast as we can, thanks to the EPA.

Cooling 1950 - 80: US, Europe, Russia, NH No warming after 2000: China Smooth trend: South America, SH Although many more factors play a vital role (see Paul S» reply), one can clearly identify the aerosol effects in the surface temperature data.

If this is right then these cloud + aerosol changes can't just be feedback from GHG warming as you seem to be suggesting.

Hmmm... don't suppose it occurred to anyone to check the amount of anthropogenic aerosols that were emitted during this time frame 1940 - 1970, or the fact that aerosols have an immediate cooling effect on troposphere temperatures that can mask the underlying warming caused by the CO2 emissions that also accompany the aerosols.

Once aerosols are that high they can spread globally, destroy the ozone layer that protects us from ultraviolet radiation and exacerbate global warming, researchers warn.»

Hence, it is more than a little tiresome to see the same old rants from skeptics who point out this period of rapid aerosol and CO2 rise as «proof» that CO2 can't possibly cause warming since this period saw cooling.

«Earth system models» include all that and much more: forests that can shrink or spread as conditions change; marine food webs that react as the oceans grow more acidic with carbon dioxide; and aerosol particles in the atmosphere that interact with greenhouse gases, enhancing or sapping their warming power.

«The second is that the natural and anthropogenic aerosols are not well - mixed geographically and can have a substantial effect on regional warming rates.

Backing that up, NASA says that 1) sea surface temperature fluctuations (El Niño - La Niña) can cause global temperature deviation of about 0.2 °C; 2) solar maximums and minimums produce variations of only 0.1 °C, warmer or cooler; 3) aerosols from natural sources such as volcanic eruptions (Mount Pinatubo for example) have caused average cooling of 0.3 °C, but recent eruptions have had not had significant effect.