Some suggest that increased atmospheric aerosol content is masking the warming from co2 that we should see, but is not currently occurring. I've not found any data that supports this conclusion, but time series data on global aerosol content is in short supply.
This data suggests that apart from volcanic events, the optical depth (how clear the air is of aerosols) is essentially stable. but the time period is only up to 2006, so may not be enough to either confirm or refute the 'masking' suggestion
http://climexp.knmi.nl/data/igacp_tau_18...
Edit trevor. Re "More recently we’ve once again witnessed the effects of global dimming. As the Asian economies expand levels of dimming agents in the atmosphere have soared".
Shouldn't we be able to see this effect? For example, if I compare Beijing (very dimmed) with Darwin (no dimming), shouldn't I see that warming has continued in Darwin, but been masked in Beijing? This doesn't appear to be evident in the data, or perhaps I have misunderstood what you meant.
Global Aerosol distribution
http://earthobservatory.nasa.gov/GlobalM...
Beijing temperature record
http://data.giss.nasa.gov/cgi-bin/gistem...
Darwin temperature record
http://data.giss.nasa.gov/cgi-bin/gistem...
The locations weren't 'cherry picked' just to make the point... Beijing was the obvious choice for dimming, and Darwin was just the first that came to mind with a long record, tropical and clean air (from looking at the animation, i picked somewhere on the east side of a land mass, and clear of aerosol change). Station history data is from here (it's just back online after a couple of months absence). http://data.giss.nasa.gov/gistemp/statio...
Aerosols have no link to global warming. Aerosols originally contained CFCs that when released into the atmosphere broke down allowing the chlorine to escape and react with O3 (ozone) in the stratosphere. This caused the hole on the ozone layer. CFCS use is now banned after the Montreal Protocol in 1987. More sunlight has always been able to reach the ground. Ithe pollution stops its heat from escaping into space. If sunlight were to be stopped by pollutants. The earth would cool down and global warming wouldn't happen
Those are different issues, the chemicals that were in aerosols were CFC's which acted as a catalyst to break down the ozone layer, that's totally unrelated to global warming. The Montreal Accord was a progressive plan to replace CFC's with other chemicals, the pollutants were not reduced, just changed to something that did not break down the ozone layer. Indeed, the replacement chemicals all have a greater greenhouse effect so the environmental efforts to protect the ozone layer has inadvertently added to the global warming problem.
You're just mixing up information.
Hi Andrew,
Factors such as the presence of aerosols in the atmosphere are indeed taken into consideration by climate scientists, so too are scores of other components that influence the global temperature.
In respect of your question, the aerosol of most interest is sulphur dioxide, chiefly produced by coal burning power stations and other industrial processes. The sulphate is released into the atmosphere where it mixes with stratospheric water vapour to produce weak sulphuric acid. The molecules of acid reflect and disperse some of the incoming solar radiation effectively acting like billions of microscopic mirrors and reducing the amount of heat energy we receive from the Sun.
Together with other pollutants, most notably black particulate matter, this absorption and reflection of solar energy is known as atmospheric dimming.
In the past, the emissions of sulphates, BPM and other pollutants went largely unchecked. Things came to a head in London in December 1952, the weather was cold, calm and damp and the misty air mixed with the pollution of the city and enveloped London in a thick blanket of smog. The smog hung over the city for five days during which time more than 10,000 people died and 100,000 fell ill.
The government responded by passing legislation that significantly reduced the emission of pollutants and in 1956 the first of the Clean Air Acts was passed. In the years that followed other countries around the world followed suit and by about 1980 the atmosphere was much improved.
A significant effect of these Acts were that they greatly reduced the level of global dimming. For decades the average global temperature had been rising but as air pollution got worse there came a point when the warming was being masked by the dimming. As a result, we had a warming atmosphere up until about 1940 then a period of some 40 years where temperatures levelled off. Once the sulphates and other emissions had been removed from the atmosphere the warming returned to the fore.
More recently we’ve once again witnessed the effects of global dimming. As the Asian economies expand levels of dimming agents in the atmosphere have soared. At present countries like China and India do not have the same emissions regulations that are in place elsewhere. In fact, the situation is so bad that the pollutants hanging over southern and eastern Asia and are visible from space as the Asian Brown Cloud.
The rate by which the planet has warmed recently is about half that which it was 20 years ago, this is the result of modern-day global dimming.
Unlike greenhouse gases that reside in the atmosphere for an average of 84 years, the pollutants that contribute to dimming are dissipated out within two to three years – a combination of being precipitated out, gravity and chemical reactions.
India and China have both stated their intention to pass their own Clean Air Acts. If they do, and they’re successful, then the present dimming will quickly dissipate and the underlying warming will bounce back, this is likely to result in the most pronounced period of warming yet.
London Smog - http://en.wikipedia.org/wiki/Great_Smog
Asian Brown Cloud - http://en.wikipedia.org/wiki/Asian_brown...
Global Dimming - http://en.wikipedia.org/wiki/Global_dimm...
Global Temperatures - http://en.wikipedia.org/wiki/File:Instru...
Many of the harmful chemicals in pressurized cans have been removed. However there is still a ton of **** getting dumped into our atmosphere, Both as greenhouse gasses and destroying ozone. The heat level will still increase.
To answer your question, even if less aerosols were being released it would only slow the rate at which the earth is warming. Not by much though
I am not sure where you get less aerosols are being released. I thought it was more.
No it is not in the computer models, they cant even get cloud formation to work yet.
There hasn't been any authentic correlation between your spray deodorant and the earth's temperature.
Less pollutants in the form of aerosols are being released, has this an effect on the Earth's temperature?
The atmosphere is considerably less polluted than previously so presumably more sunlight can get through, do the scientists take this into consideration when working out why the globe has warmed?
