Zusammenfassung der Ressource
Climate change
- climate has fluctuated
drastically
- each change, sundry species have benefited
and flourished, others adapted, faltered, or
died
- surface air temperature a half degree celsius
during this century. If the trend continues, it
could alter climate patterns worlwide
- global climate depends on combinations
of factors interacting in subtle and
complex ways that we do not yet fully
understand
- THE GREENHOUSE EFFECT
- without our atmosphere, global
temperature would be about minus 18°c
- the atmosphere, only a fraction of that heat
makes it directly back into space
- the rest trapped in the lower air
layers, wich contain a number of
gases
- that absorb the outgoing infrared radiation. gases
heat up warmth radiates back down to the surface
- caused by the predominant greenhouse gas, water vapor
- the hotter it gets, the higher the water vapor content of
the air, and the greater the greenhouse warming
- MODELS AND UNCERTAINTY
- to project future climate patterns, scientists use computer
simulations of the interactions among land, air, water, ice and
sunlight
- equations representing the know laws of atmospheric
physics and ocean circulation
- they can provide only a range of projected temperature change
- the warming could be one degree c over the next century, or it
could be as much as three times greater than that
- A CASE OF MISSING CARBON
- human activity releases approximately
7 billion metric tons of carbon
- every year adding to the 750 billion tons that is already there
- 3 billion tons remain in the air, the rest is taken
up by terrestrial and marine plants
- the ocean remove at least 2 billion tons from
the atmosphere each year
- the role of clouds and airbone suspended particles called aerosols
- clouds shade earth´s surface promoting cooling, depending on
their altitude, density and other conditions
- also they trap outgoing heat, promoting warming
- AS THE WORLD WARMS
- warming of the magnitude could also prompt
widespread calamity, more water vapor in the air
- causing more rainfall worldwide and
probably more intense weather
generally
- precipitation in any given event will be greater,
increased precipitation would be extremely uneven
- heat waves may become more seriousght
if the land has less chance to cool overni
- ANTICIPATING THE FUTURE
- a conference in kyoto, japan, in wich the industralized
nations agreed in priciple to cut their emmisions of
greenhouse gases
- some argue that hasty measures are pointless
- if all greenhouse gas emmisions stopped
tomorrow, the planet almost vertainly would
continue to warm for several decades because of
the gases
- WHAT DRIVES CLIMATE CHANGE
- weather is what happens outside your home
this morning. climate is what you can expect
to happen outside
- SOLAR INPUT
- solar energy hits the upper atmosphere at about the
intensity of three 100-watt bulbs per square yard-
one third of wich is reflected back into space
- the rest of the energy warms
earth and fuels its weather
engine
- THE ATMOSPHERE
- absorb heat energy then re-radiate a portion
of it back to the surface
- THE OCEANS
- covering 70 percent of earth´s surface,
oceans are the chief source of water vapor in
the air
- THE WATER CYCLE
- higher air temperatures can mean increased
water evaporation and the melting of sea and
land ice
- CLOUDS
- the role of clouds is poorly understood, but they
are know to both cool earth by reflecting solar
energy and warm earth by trapping heat being
radiated up from the surface
- ICE AND SNOW
- bright white expanses of ice and snow reflect sunlight
back into space, cooling the planet
- LAND SURFACE
- when solar energy penetrates the land surface it is
converted into heat, most of which radiates upwards quickly
- HUMAN INFLUENCES
- adding to the mix of greenhouse gases naturally present in
the atmosphere, human activities magnify warming effects