Atmospheric Composition and Climate

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Atmospheric Composition and Climate

• E. Mészáros
• University of Pannonia
• H-8201 Veszprém, P.O.B. 158.
• meszaroserno_at_invitel.hu

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Atmospheric cycle of different constituents

• The Earths atmosphere consists of gas molecules
  (size ?10-10 m) and aerosol particles (1-10
  nm-10 ?m).
• Atmospheric constituents are exchanged
  continuously in the air there are sources
  (mostly biogenic) releasing them into the air,
  and there are sinks removing them from the air.
• Each molecule (particle) spend a certain time in
  the air residence time. Examples oxygen 3000
  years, carbon dioxide 5 years, water 10 days.

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Biogeochemical cycle
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The Earths atmosphere is a very significant
environmental medium

• Protection against external effects meteors, UV
  radiation, cosmic radiation, etc.
• Atmospheric constituents supply nutrients for the
  biosphere water, carbon dioxide, oxygen,
  nitrogen and nitrogen compounds, sulfur species,
  etc.
• Atmospheric gases and aerosol particles control
  the solar and terrestrial radiation transfer,
  consequently the climate of the planet (the role
  of clouds).

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Interaction with the biosphere

• The majority of atmospheric gases and particles
  is produced by biospheric emissions the present
  air is the consequence of life on our planet.
  Living organisms control the atmospheric
  composition (example microbiological processes
  determine nitrous oxide emissions which controls
  the ozone layer).
• Air constituents make the life on the planet
  possible (examples photosynthesis,
  decomposition, respiration).

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Atmospheric effects on terrestrial and aquatic
ecosystems

• The different constituents leave the air by wet
  and dry deposition (sink processes). Wet
  deposition (materials removed by precipitation
  fall) is important in particular, providing for
  ecosystems (including agricultural lands)
  nitrogen (nitrate, ammonium ions) and sulfur
  (sulfate ions) containing compounds in dissolved
  form.

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Human effects on depositions

• The emissions of sulfur (by energy production)
  and nitrogen oxides increase the hydrogen ion
  concentration leading to acid rains.
• The emissions of nitrogen compounds in oxidized
  or reduced (ammonia agriculture) forms can
  contribute to eutrofication (excess nutrients
  (e.g. in shallow lakes).

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Climate depends on radiation balance
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Human activities and climate

• Emissions of certain gases and aerosol particles
  into the air modify solar and terrestrial
  radiation transfer climate changes.
• Examples
• emissions of greenhouse gases like carbon dioxide
  (fossil fuel burning), and methane (rice
  production, animal husbandry) can cause global
  warming owing to their long residence time.
• emissions of aerosol particles and aerosol
  forming gases (short residence time) can cause
  cooling due to the direct and indirect (through
  cloud formation) extinction of solar radiation.

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Present views about aqnthropogenic climate change
(IPCC, 2008)

• The increase of the concentration of greenhouse
  gases in the atmosphere is certainly caused by
  human activities.

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Continuation

• The temperature increase observed during the last
  hundred years (less than 1oC) is very probably
  man-made.

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J. Lovelock (1988 The Ages of Gaia)

• The atmosphere is the face of the planet, and it
  tells, just as do our face, its state of health
  and even if it is alive or dead.
• Conclusion Human race has to operate in such a
  way that our special atmosphere, essential for
  our own life, remain alive, that is compatible
  with our activities.

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Thank you for your attention!