Atmosphere and Lowermost Exosphere
Pp. 140-161 (22)
The anthropogenic modifications of the atmosphere's trace gases and their
heat content occurred because of world population growth, agriculture, industrial
economy, deforestation, land use change, mobility, and urbanisation. CO2
concentration increased from ca. 280 ppm in 1780 to 402 ppm in 2016 and, according
to the cumulative greenhouse effect, the near earth surface temperature rose on average
by 0,9 °C from 1850 to 2014. An estimated 2 teraT of CO2 have been emitted into the
atmosphere since 1760. The emission histories of other greenhouse gases (CO, CH4,
N2O, NOx, CFC) and their cumulative radiative forcings are given (ca. 3W/m2 relative
to 1750). NH3-emissions increased from 6 MT in 1890 to 32.5 MT in 1995. They
contribute to expansion of subtropical arid zones, northward shift of the intertropical
convergence zone, and poleward retreat of mid-latitude low-pressure tracks. The
eastern Mediterranean drought (1998-2012) is explained by climate warming.
Frequency and magnitude of events during Australian wildfire season increased
significantly from 1973-2010. Arctic amplification caused the long-lasting boreal
summer weather extremes of the last decades. SO2 pollution was reduced in
industrialised countries due to implementation of filters in the 1970s. Sources and
histories of particulate matters, as well as the development of their radiative forcings
are given. Cumulative global Hg-emissions between 1850-2010 are as much as 350,000
T. Significant decreases in particulate matter in urban air have occured since the 1920s
in developed countries. Radioactive releases due to nuclear havaries and above ground
nuclear tests are given. The stratospheric fraction of the latter persists over decades.
The lowermost exosphere is littered with astro garbage (ca. 23,000 objects), raising
safety risks of operating spacecraft.
Aerosol, Albedo, Arctic amplification, Astro garbage, Atmospheric
circulation, Climate warming, Clouds, Emission histories, Greenhouse gases,
Heat, Keeling curve, Moisture content, Ozone, Particulate matter, Pollution,
Radiative forcing, Residence time, Stratosphere, Stratospheric jets, Trace gases,
Environmental Geology, Munich, Germany.