Weather and Climate

Atomosphere ~ 78% N 2, 21% O 2, and other trace gases composed of many layers the ozone layer (O 3 )which absorbs much of the sun’s dangerous UV radiation

Atmospheric Pressure the pressure that results from the column of air above us at sea level the air above you exerts a pressure of 10.1 N/cm 2 –this is about one ton of weight on (and all around) your body!

a barometer is a machine that measures how much pressure the air is pushing down with a rise in pressure usually means improving weather while falling pressure usually means bad weather

Wind air moves from an area of high pressure to low pressure –this is down a pressure gradient that results in wind the Coriolis effect explains how the direction of the wind is influenced by the Earth’s rotation. –the earth moves faster at the equator than at the poles

In the Northern Hemisphere winds move clockwise in the Southern Hemisphere, winds move counter clockwise /es1904/es1904page01.cfm?chapter_no=visualization

The greenhouse effect

–scientists analyze tiny air bubbles trapped in ice cores to learn about past: atmospheric CO 2 concentration has increased over 25% over the last few centuries this increase correlates with increase of Earth’s temperature Siple Station, Antarctica 75°55' S, 83°55' W Warming/Cooling Trends

a natural phenomena- over the past 900,000 years, the troposphere has experienced prolonged periods of global cooling and global warming. simultaneous warming on Earth and Mars suggests that our planet's recent climate changes have a natural-- and not a human- induced cause

energy passes through the atmosphere and is then re-radiated by the surface as electromagnetic radiation of a longer wavelength (now infrared) than that of the original, incident radiation. water, CO 2, oxides of nitrogen, and methane trap infrared radiation causing global warming JUGsghttps:// JUGsg Cause

global temperature has ↑ by several degrees over past decade, glacial deposits have melted across the globe, and the recent thinning of Arctic and Antarctic ice packs may cause melting of glaciers, flooding of low- lands, more frequent storms resulting in... –decreased habitat –increase in pest species (pathogens, mosquitoes) –dozens of amphibians’ extinction are correlated with global warming Consequences of the greenhouse effect

Between 1979 and 2005, average Arctic sea ice dropped 20% (as shown in blue hues). in order to reduce the greenhouse effect-- CO 2 absorption by photosynthesis must go up and emissions from burning fossil fuels must go down.

"an ounce of prevention is worth a pound of cure", "better safe than sorry", and "look before you leap". must prove that a human-induced change will not do harm vs. it will do harm when an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically; in this context the proponent of an activity, rather than the public, should bear the burden of proof a willingness to take action in advance of scientific proof [or] evidence of the need for the proposed action on the grounds that further delay will prove ultimately most costly to society and nature, and, in the longer term, selfish and unfair to future generations." The Precautionary Principle

Justification for Action? The economic harm of measures taken now to limit global warming could outweigh the potentially much greater harm for future generations of taking no action now Is it ethical to knowingly jeopardize future human generations and damage the habitat (possibly leading to extinction) of other species?