Chapter 10: Climate - Past, Present, Future Flashcards
What is climate?
The climate is weather averaged over time. Climate fluctuates with time and is influenced by a number of factors, including human activity
What form of energy does the sun emit?
shortwave electromagnetic radiation
How is the heat emitted by the earth?
longwave infrared radiation
How much heat is emitted by the Earth?
the Earth emits enough heat to warm it up to -1 degree Fahrenheit
Why is the global mean surface temp much warmer than earths baseline of -1?
due to the greenhouse effect
Greenhouse effect
the presence of gases in our atmosphere that insulates the Earth like a blanket, trapping the longwave radiation emanating out from the Earth’s surface. Promote warming of the atmosphere
What are the natural human-made atmospheric gases that are causing the greenhouse effect? And what do these gases do?
– Water vapor: H2O
– Carbon dioxide: CO2
– Methane: CH4
– Nitrogen oxides: NOx
– Chlorofluorocarbons: CFCs
These gases trap heat and warm the lower atmosphere, similar to the effect of the trapping of solar heat by a greenhouse.
What is the Paris Climate Accord trying to do?
it is trying to limit global temperatures from rising any higher than 2 degrees celsius.
Shrinking of polar ice caps and melting
The rapid decline in the size of the polar ice caps in recent years is partly due to atmospheric circulation that has favored melting. The melting induces a positive feedback cycle warming leads to more warming which is exacerbated at higher latitudes and elevations.
Permafrost
permanently frozen ground, seen in northern latitudes above 60 degrees, underlying 20% of the land area in the world.
What happens when there is changes in permafrost?
changes affect the distribution of surface water and groundwater.
Where is the heat of absorbed by the earth stored?
The oceans store and transport a tremendous amount of heat around the globe. Much of the heat absorbed by the earth is stored in the oceans.
What causes hurricanes of greater intensity?
the increased heat supplies energy which spawn hurricanes
Thermohaline Circulation
(heat salt) the roles of temperature and salinity in moving water around the globe
Ocean conveyor belt
Global circulation of ocean waters contributes to the change.
What size belt is the Gulf Stream a part of?
is part of this larger belt of the ocean conveyer belt, whereby water surface water is transported east and north to Greenland, where it cools from contact with cold Canadian air.
Downwelling
as water cools, it increases in density and sinks to the bottom
Upwelling
where the water heats up and rises to the surface
What are the benefits of upwelling?
Water is nutrient-rich, and where upwelling occurs diverse aquatic ecosystems grow and thrive.
What is El Nino?
the periodic halt in upwelling, the fertile cold waters no longer rise up along the western south american coasts. It is part of a larger decade-long cycle where el nino is a warm phase and la nina is the cold phase
What is the result of the El Nino?
the event causes large scale changes in the pathways, frequency, and intensity of Pacific storms and timing of the monsoon season
What is the result of warmer waters?
reduces the productivity of the primary producers: phytoplankton, microscopic photosynthetic marine algae that form the base of many ecological food webs
CO2 and the Ocean
Oceans can absorb CO2 and thus helps slow the rate of global warming, CO2 levels are building up in the ocean, causing them to be more acidic
What was used to predict past global temperatures?
the abundance of oxygen 18 and oxygen 16
during ice ages, the ratio would be larger because ocean water would be enriched in Oxygen 18 and Oxygen 16 would be trapped in ice caps. Microorganisms making their shells during this cooler time would have higher concentrations of Oxygen 18
Albedo
glaciers white in color reduce global warming by reflecting sunlight back into outer space
Positive feedback cycle of climate
the warming trend reinforces itself, the more the glaciers retreat, the lower the albedo, and the more quickly earth warms up.
Negative feedback of climate
the warming induces changes that encourage the opposite (in this case cooling), due to large scale storms being more frequent
