Zusammenfassung der Ressource
The Atmosphere
- the FIRST TWO
BILLION YEARS
- the surface of the Earth was originally
molten, so super hot that any
atmosphere just boiled away into space
- after a few million years of
boiling, the planetary metaphorical
hot potato cooled down just
enough to form a thin crust
- nevertheless, volcanoes kept erupting
and spewing out loads of gases, including
carbon dioxide, water vapour and nitrogen
- we think that this was how the atmosphere was formed - if this
was the case, then the early atmosphere would've been mostly
carbon dioxide and water vapour with hardly any oxygen
- as the earthy potato continued cooling, water vapour condensed to form oceans
- the NEXT TWO
BILLION YEARS
- green plants evolved
over most of the Earth,
quite content in the
carbon dioxide-rich
atmosphere
- lots of the early carbon dioxide got dissolved into the ocean and
those happy green plants removed a whole load more through
photosynthesis, while simultaneously producing oxygen
- when plants died they were buried under layers
of sediment and the carbon that they'd removed
from the air (as carbon dioxide in photosynthesis)
became locked up in sedimentary rocks as
insoluble carbonates and fossil fuels
- this build-up of oxygen in the
atmosphere killed off some early
organisms, who couldn't tolerate it,
but allowed other more complex
organisms to evolve and thrive
- the FUTURE
- HUMAN ACTIVITY
is CHANGING the
ATMOSPHERE(!)
- the concentrations of nitrogen,
oxygen and argon in the air are
pretty much constant...
- ...BUT human activity is adding small amounts of POLLUTANTS to the air
- for example....
- carbon dioxide
- carbon monoxide
- particulates (i.e. soot etc.)
- nitrogen oxides
- sulfur dioxide
- these pollutants come from many different sources, exempli gratia...
- burning fuels
- in power stations
- in vehicles
- nature
- gases (and particulates as
well) released from volcanoes
like in the first two billion years
- some pollutants are DIRECTLY harmful to humans
- this can cause
disease (bad) or death
(worse) to people who
breathe enough in
- उदाहरण के लिये...
- carbon monoxide reduces the amount of oxygen
that the blood can carry, causing flu-like symptoms
and then death (notoriously difficult to treat)
- other pollutants are INDIRECTLY harmful
to humans, damaging our environment
- για παράδειγμα...
- sulfur dioxide can cause acid rain → pollutes
rivers and lakes → kills fish → people get hungry
- other pollutants (მაგალითად
carbon dioxide) are causing climate
change, which is big and scary and
likes to eat people and so forth
- ATMOSPHERE: "The envelope of gases
surrounding the earth or another planet"
- NOW
- by now, pretty much all of the
carbon dioxide has been absorbed
by plants, and we have been left
with the amounts of gases above...