A pool of warm surface water in Pacific Ocean sloshes btw Indonesia and South america. usually, trade winds push warm ocean water westward. but these waters are replaced by upwelling of cold, nutrient-rich deep waters (pulled from N. American coast) off south american west coast. warm water sloshes back to eastern pacific and sea levels rise along s. american w. coast
Northeasterly trade winds normally push surface water along the Pacific _____ towards ______. During el nino years, these trade winds _______ and flow eastward, towards the Americas.
cold nutrient rich water brought up from below.
eastward-flowing deep currents that periodically interfere w/ coastal upwelling warm the sea surface of s. america.
How does ENSO affect us?
During an el nino year, the northern jet stream splits and is drawn down south over US. it pulls moist air from pacific and gulf of mexico, bringing intense storms and rains from CA to midwest.
La Nina years bring hot, dry weather to same areas.
How could ENSO have a cooling effect and act as a safety valve for global warming?
Increased cloud cover would raise albedo which is good. Upwelling convection currents could pump heat into the stratosphere, which could cool the earth.
Pacific Decadal Oscillation PDO
large pool of warm water that moves back and forth across N. Pacific every 30 years. affects salmon runs
anthropogenic global climate change
human-caused climate change, one of the most important enviro issues. came from observatory on mauna loa in hawaii.
CO2 levels rose from ___ ppm in 1958 to ___ppm in 2005.
this is largely due to...
due to most of the world's land vegetation on the n. hemisphere, northern seasons dominate. co2 levels drop in may as plant growth rises bc photosnthesis.
Intergovernmental Panel on Climate Change
scientists assess the current state of knowledge about climate change.
the earth's surface temp has risen about ___ Celsius over the past century
since preindustrial times, atmospheric concentrations of ... have climbed over
CO2- 31%, about 3 bil tons per yr
methane is released by
coal plants, ruminants, wet-rice paddies, wetlands, landfills, pipeline leaks.
Nitrous Oxide is produced by
burning organic material and soil denitrification.
____ regions have warmed faster than the rest of the world. ex: alaska, canada, russia, temperatures have increased about ___ degrees C in 50 yrs
Arctic sea ice is ____% thinner now and covers ____ less area than it did a century ago.
90% of glaciers on Antarctic Peninsula are retreating an average of ___ m per yr
Greenland's ice cap holds enough water to raise sea level by about ___ m if it melts
so far, oceans have been buffering effects of greenhouse emissions by
absorbing CO2 directly and storing heat.
However, oceans are absorbing ___ watts per m2 more than is radiated back to space. this absorption slows current warming, but means that it will still take centureies to set off the stored heat.