Week 8 - Future Climates Flashcards
What are the Milankovich Cycles?
Changes in Earth’s orbit around the sun.
What are the three basic types of Milankovich Cycles?
Eccentricity, tilt of the rotation axis, and procession of the equinoxes.
What is eccentricity?
Changes in the elliptical nature of Earth’s orbit around the Sun. High eccentricity means more elliptical, low eccentricity means more circular.
What do the Milankovich Cycles explain?
Glacial and inter-glacial periods.
What does tilt of the rotation axis mean?
It varies 1.5 degrees in either direction; essentially, we are moving the polar circles and tropics.
What is the procession of the equinoxes?
The wobble of a top; essentially, it changes which hemisphere points toward the sun when the Earth is closest to the sun.
How are the effects of the Milankovich cycles amplified?
The can be amplified by coinciding with each other, volcanic activity, El Nino, and greenhouse gas warming.
What effect does volcanic activity have on climate?
It can produce short term cooling by ejecting ash into the atmosphere, increasing albedo and essentially blocking out the sun.
Explain the carbon cycle.
Terrestrial vegetation absorb carbon until their deaths when they will release carbon under dry conditions and methane under wet conditions. We have not been able to quantify the oceans’ contribution to the carbon cycle yet.
Describe and explain the post-industrial increase in carbon dioxide levels in the atmosphere.
There was a sudden spike in carbon dioxide levels in the atmosphere around the 1700’s because of the Industrial Revolution. All of a sudden, we were burning coal.
What is the role of natural and anthropogenic factors in climate change?
They both contribute and both can have “forcing” effects.
Why is there stratospheric cooling?
There is less ozone to absorb ultraviolet radiation.
Explain how climate change models work.
We are interested in energy in and out, and how this is distributed over the Earth; we wrap our model Earth in a series of little boxes, run some fancy math, and then study what happens in these little cubes and the interrelation among all the cubes.
What are scenarios?
We don’t have climate forecasts because human activity and choice will affect what happens, so we model possible scenarios. There is no predestined amount of carbon that will be in the atmosphere.
What are three likely impacts of climate change on human health?
It will alter the distribution of some infectious disease vectors (e.g. mosquito distribution), it will alter the seasonal distribution of some allergenic pollen species, and it will increase heat-wave related deaths (e.g. 15 000 in France that one year!).
