20. Climate Change Flashcards
What did Einstein say about energy? What does this mean for any system?
Energy cannot be created or destroyed: it is conserved
Energy input- energy output = change in energy storage
rate of energy addition- rate of energy subtraction=
rate of change of stored energy
more ___wave energy is absorbed in the tropics, and __wave emission is relatively smaller
short
long
For any planet in space, energy input=
solar radiation absorbed
for any planet in space, energy output=
solar and longwave radiation lost to space
T/F
If the stored energy on a planet is not changing, then energy input= energy output
true
Absolute zero=
the lowest temperature possible. At a temperature of absolute zero, there is no motion and no heat
0 degrees kelvin/ -273C
What must be true for an object to emit longwave radiation?
any object that contains heat (ie is above absolute zero) emits longwave radiation
At what rate does an object emit longwave radiation?
Emits LW radiation at a rate proportional to its temp
L=σT^4 over its entire area
The steady state global energy balance assumes energy stored ___(is or is not changing)
NOT changing
Give the equation for earth’s energy balance
write it down
Based on the Earth’s energy balance equation, what is the temperature required for the Earth’s outgoing radiation to balance the incoming solar radiation?
255K or -18C
This is not the actual avg temp of the earth!
Earth’s average temp is 33C warmer than it should be according to the earth energy balance equation. Why?
Because for that equation, we assume no atmosphere, which is not true.
Greenhouse effect!
T/F
The atmosphere easily transmits solar radiation but almost completely absorbs earth’s longwave radiation
true
What kind of radiation does earth’s sfc emit? Is it absorbed?
longwave radiation
it’s absorbed by certain atmospheric gases and clouds
*the atmosphere almost completely absorbs outgoing LW
T/F
The atmosphere emits LW radiation in one direction: out to space
false
emits LW in ALL directions, including back towards earth, heating it
Give the 5 primary gases that absorb earth’s outgoing LW radiation. What are these known as?
- H2O (water vapor)
- CO2
- CH4 (methane)
- N2O (nitrous oxide)
- O3 (ozone)
= The Greenhouse Gases
Explain what happens to the heat when more GHG are present in the atmosphere
More LW radiation is absorbed by these atmospheric GHG, so less heat energy is emitted to space. This results in the Earth’s temp increasing
Climate=
avg atmospheric conditions that prevail in a region over extended time span (usually min 30 yrs)
Give the 5 main components of the earth system.
These components determine climate
Atmosphere
Vegetation
Ice
Ocean
Land Surface
When one component of the Earth climate system changes, what happens to the others?
When one component changes, the others react (likely also change)
Changes in the 5 components of the climate system are analyzed in terms of which 2 things?
Cause (forcing)
and
effect (response)
Describe what “climate forcing” is
= a factor that causes changes in the climate system (energy budget)
eg. differing sun cycles, changes in albedo, etc
How often do earth-orbital changes occur? Do these contribute to alternating glacial/ interglacial periods or not?
occur over 10s to 100s of thousands of years
yes
Describe the following earth-orbital changes
- precession
- obliquity
- eccentricity
- precession= the direction that earth’s axis of rotation is pointed
- obliquity= angle earth’s axis is tilted with respect to the earth’s orbital plane
- eccentricity= shape of earth’s orbit
describe 2 ways in which incoming solar radiation can change, causing changes in the climate (climate forcing)
- Sun cycles= internal variations in the strength of the sun
- Earth-orbital changes= alter the amount of solar radiation received on earth by season & latitude
Give 4 types of climate forcing that are not related to sun cycles or earth orbital changes
- changes in earth’s albedo: distribution of land masses/ ecosystems & their snow cover
- Tectonic processes: alter ocean circulation and distribution of heat
- volcanism= aerosols + tectonic control of CO2 - Changes in atmospheric composition: eg. early evolution of plant life/ volcanic outgassing changes output of GHG
- Anthropogenic climate forcing: changes in atmospheric comp. from emissions, land use changes albedo
Paleoclimatology=
the study of past climate using archives (techniques such as radioactive isotopes, fossils, annual layers, etc)
Different components of the climate system have different response times. What does this mean?
= time it takes to fully react to an imposed change
Can be hours to thousands of years
T/F
The atmosphere has a very fast response time & land sfc reacts more slowly
true
but land sfc still shows heating & cooling changes on time scales of hours to weeks
What is the relative response time of water?
Slower than air/ land because of its heat capacity
Upper ocean= weeks to months
Deeper ocean= decades to centuries
Explain the long term carbon exchanges between volcanos and chemical weathering
- volcanic input of C from rocks to atmosphere
- removal of CO2 from atmosphere by chemical weathering
Removal of C via chem weathering must balance changing volc inputs over long timescales
Describe how chemical weathering is influenced by:
- temp
- precip
- vegetation
- Temp inc= weathering inc
- precip inc= weathering inc
- veg inc= weathering inc *?
During warm periods, how does chemical weathering influence the temp?
during warm periods, weathering removes CO2 from the atmosphere faster than volcanoes can build it up
- this causes the total volume of CO2 to go down, cooling the planet
During cool periods, how does chemical weathering influence the temp?
During cold periods, volcanoes add CO2 faster than it can be removed by chem weathering, warming the planet
Climate variability=
the way climate fluctuates yearly above or below a long term avg value
climate change=
long-term continuous change (inc or dec) from avg weather conditions
- slow & gradual, unlike weather variability
- it’s difficult to perceive without scientific records
T/F
Climate change is the same as climate variability
false
Zoom out and look at climate change in the past 100 million years. What did the climate look like at each of the following times?
- 100 million years ago
- 21,000 years ago
- 1830s
- 1930s
- 100 million years ago: warmer conditions had eliminated ice from the face of the earth
- 21,000 years ago: climate was so cold that huge ice sheets covered CAN and N. Europe (sea level was ~120m lower than present)
- 1830s: air temps were cooler than now
- 1930s: hot, dry interval produced the dust bowl
T/F
Faster changes in climate at shorter timescales are embedded in and superimposed on the slower changes at the longer time scales
true
What is the Intergovernmental Panel on Climate Change?
IPCC= the United Nations body for assessing the science related to climate change
T/F
Global Warming means it is getting warmer in every single point of the earth
false
It’s an AVERAGE increase in global temp
T/F
Global warming does not mean that each year is successively warmer than the previous one
true!
This is just interannual variability
When studying recent global warming, surface temperature measurements have some uncertainty. How do we decrease this uncertainty?
Analyze other parts of the climate system, not just the sfc
[GHG] in 2011 exceeded the range of [ ] recorded in ice cores during the past ___ years
800 000 years
What are shared socioeconomic pathways (SSPs)?
= projections of future emissions that take into account a wide range of socioeconomic factors like pop and GDP
Does the IPCC predict an inc or dec in the following?
- global temp change
- global land precip change
- sept arctic sea ice area
- global mean sea level change
- inc
- inc
- dec
- inc
Is it likely that our current global warming is due to sun cycles?
No
Current research shows an imbalance at the top of the atmosphere
- more energy absorbed, less emitted= avg temp of earth is increasing
T/F
CO2 always legs temperature
false
It can, but it doesn’t have to
- feedbacks are very important! CO2 acts as a forcing sometimes, and sometimes as a positive feedback on climate change
__% of climatologists who are active publishers on climate change believe that human activity is a significant contributing factor in changing mean global temperature
97%
93% of the extra energy from enhanced greenhouse warming has been absorbed by the _____
oceans!
Oceans are a major heat & C sink
The oceans have absorbed a lot of the extra energy from greenhouse warming. Give ~4+ impacts this has had on the oceans
- more frequent extreme El Nino events
- inc in ocean temp
- inc in ocean stratification
- changes in ocean circulation
- sea level rise
- acidification
- harmful algal blooms
