For a long time I’ve been suggesting that reductions in the level of pollution from the 1970s clean air acts was likely to have caused some if not all the warming from the 1970s to the point that clean up effectively came to an end which is around 2000.
And if you look at almost every early picture of the past (before 1970s), what you will see is a clear smog haze created from the burning of coal high in sulphur.
It is hard, not to miss the obvious impact of pollutants in the past, unless that is, you are intentionally ignoring them because your real agenda is not to clean up pollution, but to destroy the modern industrialised economies of the West.
When looking at global temperatures I discovered what is clearly the smoking gun in that the warming from 1970-2000s occurred, not globally as would occur for CO2, but in regional hotspots about 3days downwind from the large 1970s economic zones as shown below.But this issue has become very problematic for those trying to ignore the massive changed due to the clean air acts of the 1970s. Because as the pause continues year after year, and the public just aren’t buying their made up data with the “added warming” flavour, on the one side alarmists want to use the recent increase in Chinese pollution to explain the lack of recent global warming – so a lot of work has gone into proving “it was the Chinese wot done it”. But by the same token, if Chinese pollution could stop warming now, then the reduction in pollution in other areas would cause warming.
So it’s great to see that Climate Depot have understood that 1970s pollution is a perfectly viable explanation of much of recent climate:
- Up to 1970s we saw increasing economic activity with associated pollution and we saw the global cooling scare
- From 1970-2000 concerted efforts were made by the advanced countries to clean up pollution and as a result we saw the cooling-pollution removed which resulted in a very predictable and short-term increase in temperature
- From 2000 not only was the effect of 1970s clean air acts coming to an end but there was increasing pollution from countries like China – and we saw the Pause.
And the alarmists ask? “How can you explain 20th century warming without CO2?” The real problem is how do you explain 20th century climate and the very regionalised nature of 1970-2000 with CO2!
The New/Old Consensus?! Pollution is ‘helping to cool the climate’ – Cleaning Up Air Pollution May Strengthen ‘Global Warming’
That means efforts worldwide to clean up the air may cause an increase in warming, as well as other climate effects, as this pollution disappears.
New research is helping to quantify just how big that effect might be. A study published this month in the journal Geophysical Research Letters suggests that eliminating the human emission of aerosols—tiny, air-polluting particles often released by industrial activities—could result in additional global warming of anywhere from half a degree to 1 degree Celsius.
This would virtually ensure that the planet will warm beyond the most stringent climate targets outlined in the Paris climate agreement. World leaders have set an ambitious goal of keeping global temperatures within 1.5 to 2 degrees Celsius of their preindustrial levels. But research suggests the world has already warmed by about 1 degree—meaning even another half a degree of warming could push the planet into dangerous territory.
“Since we’re trying to keep to a 1.5- or 2-degree target, then this is something we still need to keep in mind,” said Bjørn Samset, a climate scientist at Norway’s CICERO Center for International Climate Research and the study’s lead author.
The research also suggests that removing aerosols could have striking regional consequences by causing major changes in precipitation and other weather patterns in certain parts of the world. Aerosols don’t linger in the atmosphere for very long, meaning they don’t have time to spread around the world the way carbon dioxide and some other greenhouse gases do. Their effects tend to be strongest in the regions where they were emitted in the first place.
This means the places where air pollution is most severe are likely to experience some of the greatest effects if that pollution were to disappear. East Asia, where aerosol emissions are some of the highest in the world, would be likely to experience a strong increase in precipitation and extreme weather events. To a certain extent, these effects might carry over to other parts of the Northern Hemisphere, which are connected to Asia via major atmospheric currents.
“We also see that the impact that these aerosols have on temperature in Asia really transports northwards to the Arctic region, northern Europe, Norway, the northern U.S.,” Samset noted. “That part of the world is also quite sensitive to the changes in aerosols in Asia.”
Scientists have long known that some types of pollution can actually help cool the climate. Certain aerosols—sulfate, for instance—can reflect sunlight away from the Earth or enhance sun-reflecting cloud cover. As nations around the world have begun to crack down on air pollution, scientists have grown interested in figuring out how much extra warming might be expected as they disappear. This is critical information for strategizing ways to meet global climate goals, like the 2-degree target.
The new study relied on four global climate models, which the researchers used to simulate the effects of removing all human-caused emissions of the major aerosols, including sulfate and carbon-based particles like soot. The resulting global warming, they concluded, would be anywhere from 0.5 to 1.1 degrees Celsius.
These results are in line with other studies that have investigated the cooling “mask” of aerosols. A 2016 paper published in Nature Geoscience found that up to a half-degree Celsius of the warming that has been observed in the Arctic—the most rapidly warming region on the planet—since 1980 was caused by pollution reductions in Europe. Like the new study, those findings speak to both the considerable cooling effect aerosols have had on the climate and to the atmospheric linkages between different regions of the Northern Hemisphere.