Sentences with phrase «about aerosol cooling»

... http://www.nature.com/news/2010/100922/full/467381a.html To make it clearer that Nature News wasn't misrepresenting them Andrew Revkin solicited their views in email at the same time and printed it on his blog: http://dotearth.blogs.nytimes.com/2010/09/22/a-sharp-ocean-chill-and-20th-century-climate/ There were other comments at the time from researchers, e.g. Roger Pielke Sr. http://pielkeclimatesci.wordpress.com/2010/09/23/comment-to-andy-revkin-on-the-dot-earth-post-a-sharp-ocean-chill-and-20th-century-climate/ So you are entitled to your views about aerosol cooling but you can't claim there is no controversy or on - going debate.

But the new evidence about aerosol cooling is not reflected in the computer climate models.

Not exact matches

Researchers sought to learn more about the impact of a process in which volcanoes give off aerosol particles that reflect sunlight, cooling the atmosphere and leading to reduced rainfall.

Other aerosols can bring about temporary atmospheric cooling, mainly by seeding clouds that linger in the atmosphere longer than they normally would, or by scattering light.

The total forcing from the trace greenhouse gases mentioned in Step 3, is currently about 2.5 W / m2, and the net forcing (including cooling impacts of aerosols and natural changes) is 1.6 ± 1.0 W / m2 since the pre-industrial.

The cooling effect from this aerosol forcing is thought to be about half that of greenhouse gases, but in the opposing (cooling) direction.

I'm sorry if it's boring — only as boring perhaps as unscientific guesswork about the extent of aerosol - induced cooling post-1940s perhaps, which many are more than happy to indulge in.

Thirdly, there were concerns about the relative magnitudes of aerosol forcing (cooling) and CO2 forcing (warming), although this latter strand seems to have been short lived.

1974 Serious droughts since 1972 increase concern about climate; cooling from aerosols is suspected to be as likely as warming; journalists talk of a new ice age.

impression that, besides the study I linked to, most recent studies showed the aerosol cooling to be right about.5 degrees C.

The total forcing from the trace greenhouse gases mentioned in Step 3, is currently about 2.5 W / m2, and the net forcing (including cooling impacts of aerosols and natural changes) is 1.6 ± 1.0 W / m2 since the pre-industrial.

From about 1945 - 60 the world had a slight cooling due to those aerosols.

Let's see... many models show that aerosols could have been artificially keeping the world's average surface temperature cooler by about 3 - 5 degrees C from 1900 - 2000 --(sulfate aerosols certainly have some certifiable cooling effects cancelling out the warming effects of CO2).

Rough calculations show if you drill about a dozen mine shafts as deep as possible into the thing, and plunk megaton nuclear bombs down there, and then fire them off simultaneously, you'll get a repeat of the Long Valley Caldera explosion of about 800,000 years ago — which coated everything east of it with miles of ash and injected a giant aerosol cloud into the stratosphere — the ash layer alone formed a triangle stretching from the caldera to Louisiana to North Dakota, including all of Arizona and most of Idaho and everything in between — I bet that would have a cooling factor of at least -30 W / m ^ 2 — and you could go and do the Yellowstone Plateau at the same time — geoengineering at its finest.

Your estimates of climate sensitivity come from the IPCC, which assumes that aerosols will continue to provide a very strong cooling effect that offsets about half of the warming from CO2, but you are talking about time frames in which we have stopped burning fossil fuels, so is it appropriate to continue to assume the presence of cooling aerosols at these future times?

If industry - generated aerosols have a more limited cooling effect than originally thought, we can clean up and scale down dirty coal plants without worrying too much about consequent sudden jumps in global temperatures of up to 2 degrees C (if I remember the upper limits of earlier studies correctly).

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.

On the geo - engineering side, they have talked for decades about engineered aerosols having a pronounced cooling effect.

If only GHG forcing is used, without aerosols, the surface temperature in the last decade or so is about 0.3 - 0.4 C higher than observations; adding in aerosols has a cooling effect of about 0.3 - 0.4 C (and so cancelling out a portion of the GHG warming), providing a fairly good match between the climate model simulations and the observations.

The localized cooling between about 1950 and 1970 over industrial regions such as Europe and Southeast Asia, where anthropogenic sulfate aerosol loadings were high, is consistent with the expected cooling effect of sulfate aerosols.

Aerosol cooling from volcanoes becomes irrelevant, etc. (ii) But even if I had based it on the point that averaging n times as many samples reduces the expected error by sqrt (n), what is «erroneous» about that?

The overwhelming uncertainty in determining TCR from historical data is the uncertainty about the historical net warming or cooling effects of aerosols as discussed in Lewis and Curry (2014).

For various reasons Eli has been thinking about aerosols and how the mid-century cooling is attributed to them.

Aerosol cooling probably reduced global warming «by about half over the past century».

«Today, Hansen's team estimates the human forcing from greenhouse gases to be about 3 watts per square meter (warming) and the forcing from aerosols to be about minus 1.5 watts per square meter (cooling).»

Serious droughts and other unusual weather since 1972 increase scientific and public concern about climate change, with cooling from aerosols suspected to be as likely as warming; journalists talk of ice age.

Then, after giving a talk to the Bush - Cheney White House, he agonized about whether he should have ignored the cooling effects of aerosols because it gave Cheney an «out,» enabling him and others to make the specious argument that aerosols somehow balance out the trillions of tons of CO2 emitted every year.

WRT mid-century cooling, I don't know why you would say there is no data about aerosols, or why you think it is suspect to come up with an explanation after something happens.

For example, under the ranges stated by the IPCC, the world might well have cooled 0.1 degrees over the six decades — greenhouses gasses could have produced 0.5 degrees of warming and aerosols -0.6 degrees — and Nuccitelli would still be worrying about global warming.

If however you claim that this aerosol cooling was not really there, as you have to for the realclimate exercise (and perforce Gavins previous arguments about that were wrong too), then there is considerably more natural variation than anyone assumed and hence who is to say that we are not in another temperature blip as per the 40's.

From the IPCC AR4 report, FAQ2.1, Figure 2, the net effect of anthropogenic aerosols is clearly negative (cooling), totalling about -1.2 W / m2 since the dawn of the industrial era in 1750 to 2005.

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.

«About» ought to be in italics because we really don't know how much cooling is caused by other emissions, like particulate aerosols that go up the smokestack along with the carbon dioxide.

There were a few papers out at the time about the potential for cooling the planet through human aerosol emissions.

... Schneider became aware that he had overestimated the cooling effect of aerosols, and underestimated the warming effect of CO2 by a factor of about three.

I would like to focus on what James said about sulphate aerosols acting as a cooling agent.

In fact, I don't think I have much to argue about your initial post but it does relate directly to the famous issue of the 40s - 70s global cooling, and the alleged aerosols explanation.

The Sulfate cooling mechanism is also evidenced whenever there is a high ejecta mass volcanic eruption, which causes a measurable cooling effect, for about 3 years after an eruption; until the sulfate particulate aerosols diminish in the atmosphere to the point that they become negligible.

They come up with all kinds of hypothetical feedback mechanisms involving more natural aerosol emissions in response to global warming: Dimethylsulfide from marine phytoplankton (although a very intriguing possibility, this has never been confirmed to be a significant feedback mechanism, and there is ample evidence to the contrary, which is omitted from the report), biological aerosols (idem), carbonyl sulfide (idem), nitrous oxide (idem), and iodocompounds (idem), about which they write the following: «Iodocompounds — created by marine algae — function as cloud condensation nuclei, which help create new clouds that reflect more incoming solar radiation back to space and thereby cool the planet.»

There is no obvious answer, unless you look to stratospheric aerosol cooling — in the stratosphere, you'd need about 10 % of the sulphates you'd require in the troposphere for the same cooling effect.

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.

About «nuclear winter», is it foolish to think that aerosols released from nuclear testing in upper atmosphere have contributed to the cooling phase 1950 - 70?

Barry (# 28) Yes I appreciate that * anthopogenic global warming has not been proven, there being unknowns that we know about but can not quantify, eg ocean heat content and aerosol cooling, that may or may not act as a pipeline of future warming.

1974 Serious droughts since 1972 increase concern about climate, with cooling from aerosols suspected to be as likely as warming; scientists doubt all theories as journalists talk of a new ice age.

About 90 % or more of the rest of the committed warming of 1.6 °C will unfold during the 21st century, determined by the rate of the unmasking of the aerosol cooling effect by air pollution abatement laws and by the rate of release of the GHGs - forcing stored in the oceans.

The majority was concerned about human influences on climate, but were uncertain which would prove larger: CO2 warming or cooling from aerosols.

In the 1970s, a few scientists wondered whether the cooling effect from aerosols would be greater than the heating produced from greenhouse gases, and some popular publications ran articles about a new Ice Age.

That is a nod to the discussion about aerosol - induced cooling in the early 1970s.

The story revolves around a paper that Paul Crutzen (Nobel Prize winner for chemistry related to the CFC / ozone depletion link) has written about deliberately adding sulphate aerosols in the stratosphere to increase the albedo and cool the planet — analogous to the natural effects of volcanoes.

(By the way, for those of you who already know about global cooling / dimming and aerosols, I will just say for now that these effects can not be making the blue line go down because the IPCC considers these anthropogenic effects, and therefore in the pink band.