Lecture 13: Climate Change Flashcards
Explain what the greenhouse effect is
Shortwave radiation (insolation) passes through the atmosphere to the surface where it is absorbed.
The surface emits longwave radiation which is selectively absorbed in the atmosphere (by greenhouse gases and clouds).
The atmosphere in turn emits longwave radiation, much of which is directed towards the surface.
Thus, the surface receives energy from the Sun and the atmosphere (as there is a cycling of energy between the surface and
What is the outcome of the greenhouse effect?
An increase in radiant energy retained in the system and warming of the planet surface, oceans and the lower atmosphere, often called global warming
What are the 5 primary greenhouse gasses?
- water vapour (H2O)
- carbon dioxide (CO2)
- methane (CH4)
- nitrous oxide (N2O)
- CFC’s and others
Fossil-fuel combustion, industrial processes, deforestation and other human activities have increased our output of ______ to the atmosphere in recent decades.
carbon dioxide
What are the 4 mechanisms of natural climate change?
Solar variability
Earth’s orbital cycles
Continental position and Topography
Atmospheric gasses and aerosols
What are sources of methane related to human activities (anthropogenic)?
include livestock and rice cultivation, burning, natural gas delivery, landfills and coal mining.
At what percent did the methane and nitrous oxide concentrations raise since the mid 1700s.
150% methane, 15% nitrous oxide
How do we measure climate change?
Use instrumental records from climate stations and ocean observations
How can we determine the significance of the current warming?
Examine climates of the past
What are sources of paleoclimatic data that can be used to reconstruct climates in the past.
Tree-Rings, Pollen, Stable Isotopes, Speleothems, Lake Sediments
How can we predict the likely future change in climate?
By modeling future climate, such as a GCM (general circulation models or global climate models)
_____ is a technique for long-term climatic reconstruction that uses the atomic structure of chemical elements, specifically the relative amounts of their isotopes, to identify the chemical composition of past oceans and ice masses.
Isotope analysis
When looking at tree rings, wider rings relate to ____ growth and narrow rings refer to _____ growth.
Good, bad
The term radiative ______, also called climate ______, describes the amount by which some perturbation causes Earth’s energy balance to deviate from zero; a positive forcing indicates a warming condition, a negative forcing indicates cooling.
forcing
True or False Volcanic eruptions generate aerosols which have a warming effect.
false, cooling effect
