We have recently discussed several papers which have found substantial global dimming as a result of
increased human aerosol emissions from 1950 to 1980 and 2000 to 2010.
Not exact matches
China «could cause some decreases [in stratospheric
aerosols] if that is the source,» Neely says, adding that growing SO2
emissions from India could also
increase cooling if
humans are the dominant cause of injecting
aerosols into the atmosphere.
A few of the main points of the third assessment report issued in 2001 include: An
increasing body of observations gives a collective picture of a warming world and other changes in the climate system;
emissions of greenhouse gases and
aerosols due to
human activities continue to alter the atmosphere in ways that are expected to affect the climate; confidence in the ability of models to project future climate has
increased; and there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to
human activities.
When
aerosols from
human activities such as industrial plant and vehicle
emissions are added to the system, the energy budget has to deal with the
increase.
Analyses of the ground and aircraft data performed by Setyan et al. (2012), Shilling et al. (2013), and Kleinman et al. (2016) showed that organic
aerosol production
increased when
human - caused
emissions from Sacramento mixed with air rich in isoprene, an organic compound wafting from many plants that originate in the area's foothills.
26 Sun Stepped Art
Aerosols Greenhouse gases Warming from decrease Cooling from
increase CO 2 removal by plants and soil organisms CO 2
emissions from land cleaning, fires, and decay Heat and CO 2 removal Heat and CO 2
emissions Ice and snow cover Natural and
human emissions Land and soil biotoa Long - term storage Deep ocean Shallow ocean Troposphere Fig. 20 - 6, p. 469
25 Fig. 20 - 6, p. 469 Troposphere Cooling from
increase Aerosols Warming from decrease Green - house gases CO2 removal by plants and soil organisms CO2
emissions from land clearing, fires, and decay Heat and CO2
emissions Heat and CO2 removal Deep ocean Long - term storage Land and soil biotoa Natural and
human emissions Shallow ocean Sun Ice and snow cover
Note that while the BEST approach is based on correlations, they are correlations of variables with known causal relationships (i.e. an
increased greenhouse effect is known to cause global warming), although they do not appear to have considered some important influences like
human aerosol emissions or the El Niño Southern Oscillation.
Examining the output of climate models run under
increases in
human emissions of greenhouse gas and
aerosols, Troy Masters noted a robust relationship between the modeled rate of heat uptake in the global oceans and the modeled climate sensitivity.
In other words, the slowed surface warming isn't a result of a smaller global energy imbalance due to factors like
increased cooling from
human aerosol emissions.
These were local phenomena and there are no empirical data supporting the notion that
human aerosols caused a 30 - year cycle of slight global cooling, despite rapidly accelerating
increases in CO2
emissions and concentrations.
The identification of other, sometimes more powerful, greenhouse gases such as methane, the contributions to atmospheric carbon dioxide from other
human activities such as deforestation and cement manufacture, better understanding of the temperature - changing properties of atmospheric pollution such as sulphur
emissions,
aerosols and their importance in the post-1940s northern hemisphere cooling: the knowledge - base was
increasing year by year.
Emissions of carbon dioxide, methane, nitrous oxide and of reactive gases such as sulphur dioxide, nitrogen oxides, carbon monoxide and hydrocarbons, which lead to the formation of secondary pollutants including
aerosol particles and tropospheric ozone, have
increased substantially in response to
human activities.