Did Clean air legislation caused 1970s warming?

I was recently pointed in the direction of a paper by Dr Stephen Schneider, perhaps the most media-exposed Greenhouse expert, having developed a charismatic speaking style, complemented by his 1970s good looks, and penchant for extravagant claims about impending environmental disaster. For example, in a TV interview in 1990 to Britain’s Channel 4, he remarked

“The rate of change is so fast that I don’t hesitate to call it potentially catastrophic for ecosystems.”

The quote that caught my eye was this:

… estimates were made of the effects on global temperature of large increases in the amount of CO2 and dust in the atmosphere. It is found that even an increase by a factor of 8 in the amount of CO2, which is highly unlikely in the next several thousand years, will produce an increase in the surface temperature of less than 2 deg. K.

However, the effect on surface temperature of an increase in the aerosol content of the atmosphere is found to be quite significant. An increase by a factor of 4 in the equilibrium dust concentration in the global atmosphere, which cannot be ruled out as a possibility within the next century, could decrease the mean surface temperature by as much as 3.5 deg. K.

So, he is very clearly saying that increases in dust in the atmosphere have a much higher impact than CO2. gwAbove is the ubiquitous global warming graph – which we all know so well. Note the rise from the 1970s onward. Below are two graphs showing how air pollution has come down since the 1970/80s

Annual Mean Black Smoke Concentration 1962-1993 across the basic urban planning network in the UK

Annual Mean Black Smoke Concentration 1962-1993 across the basic urban planning network in the UK

Air Quality NO2, SO2, CO 1980-2008

Air Quality NO2, SO2, CO 1980-2008

This is supposedly one of the great victories of the environmental movement: reduced atmospheric pollution. Most of the change occurred after the introduction of clean air acts and a change from coal to less polluting fuels such as gas. According to the environmentalists, there is no connection between the drop in air particulates and the rising temperature in the 1970s.

I strongly believe the two a connected.


Abstract from Schneider’s paper

ATMOSPHERIC CARBON DIOXIDE AND AEROSOLS:
Effects of Large Increases on Global Climate.

Abstract. Effects on the global temperature of large increases in carbon dioxide and aerosol densities in the atmosphere of Earth have been computed. It is found that, although the addition of carbon dioxide in the atmosphere does increase the surface temperature, the rate of temperature increase diminishes with increasing carbon dioxide in the atmosphere. For aerosols, however, the net effect of increase in density is to reduce the surface temperature of Earth. Becuase of the exponential dependence of the backscattering, the rate of temperature decrease is augmented with increasing aerosol content. An increase by only a factor of 4 in global aerosol background concentration may be sufficient to reduce the surface temperature by as much as 3.5 deg.K. If sustained over a period of several years, such a temperature decrease over the whole globe is believed to be sufficient to trigger an ice age.

The rate at which human activities may be inadvertently modifying the climate of Earth has become a problem of serious concern 1 . In the last few decades the concentration of CO2 in the atmosphere appears to have increased by 7 percent 2 . During the same period, the aerosol content of the lower atmosphere may have been augmented by as much as 100 percent 3 .

How have these changes in the composition of the atmosphere affected the climate of the globe? More importantly, is it possible that a continued increase in the CO2 and dust content of the atmosphere at the present rate will produce such large-scale effects on the global temperature that the process may run away, with the planet Earth eventually becoming as hot as Venus (700 deg. K.) or as cold as Mars (230 deg. K.)?

We report here on the first results of a calculation in which separate estimates were made of the effects on global temperature of large increases in the amount of CO2 and dust in the atmosphere. It is found that even an increase by a factor of 8 in the amount of CO2, which is highly unlikely in the next several thousand years, will produce an increase in the surface temperature of less than 2 deg. K.

However, the effect on surface temperature of an increase in the aerosol content of the atmosphere is found to be quite significant. An increase by a factor of 4 in the equilibrium dust concentration in the global atmosphere, which cannot be ruled out as a possibility within the next century, could decrease the mean surface temperature by as much as 3.5 deg. K. If sustained over a period of several years, such a temperature decrease could be sufficient to trigger an ice age!

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2 Responses to Did Clean air legislation caused 1970s warming?

  1. Fellas, do you want to learn about ”the earth’s SELF ADJUSTING TEMPERATURE MECHANISM? Here is a sample:
    When is a solar eclipse – on part of the planet is full eclipse for 6 minutes / partial eclipse for 20 minutes – the big part is only partial eclipse – but doesn’t produce enough GLOBAL cooling – not enough to cool one beer. 2] Mercury blocks 5% of the sunlight all day – that means: as if the sun didn’t exist for 30 minutes. Presume: if it wasn’t any sun; earth’s temperature would have being close to ultimate zero Kalvin. From ultimate zero – to +15C above zero – if you take 5% of it – that’s how cold the planet would have got, would have gone colder by 12C; when mercury is in-between – IF IT WASN’T FOR planet’s self adjusting temp mechanism / oxygen & nitrogen shrinking instantly, when cooled. But, unless you are into astronomy or astrology – you wouldn’t even know that Mercury is blocking part of the sun. Meteorologist don’t even take in consideration for predicting next day’s temp; if Mercury or Venus is in-between the sun / earth. Each one of them blocks 5% of the sun’s light, not to come here, but no cooling

    SAME goes for any unusual extra warming – atmosphere expands extra, instantly and releases extra heat. Same as: when you are in the car, driving fast and is hot inside – stick the arm outside the window -> release more heat / intercept extra coldness and equalizes in a jiffy. Well the planet travels faster than your car, into that empty cold space.- warmer = volume of the troposphere increases , which means: bigger volume/expouser. The troposphere is like piano accordion.
    See, the truth is not painful… only the truth will win on the end!!!

  2. That China has been industrialising and producing such pollution was the first excuse given by the alarmists for the “pause”, then they came up with the “ocean ate it” one. I doubt if this one is more robust but we will see after others have checked it out.

    However if there is even a slight amount to it it shows that any putative warming could be reversed by putting sulphur dioxide crystals in the stratosphere. Though Prof Wood’s assessment that reversing CAGW this way would cost $100 million a year may now be on the high side 😉
    http://a-place-to-stand.blogspot.co.uk/2006/12/geo-engineering-politically-incorrect.html

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