Chapter 27: Climate ChangeFINAL:10 short answer questions

TA wrote two of them Highlight on paper

If you write down models, make sure you understand the concept rather than what they’re saying

If there’s math, will be simple 4-5:30 in Young CS50 Multiple choice questions Make sure to learn major concepts of the course

Climate Change:Four of the biggest issues we’re facing on the planet:

Loss of soil fertility Change of habitat Loss of biodiversity Climate Change

Incredible amount of feedback loops, both positive and negativeCan change the system and see little response for a while, but all of the sudden see massive response tipping point

some models are trying to take into account when this threshold is reached

The Ecology of Climate Change

Earth’s rotation affects the amount of sunlight striking the different parts of the globe and causes the seasons

Tilt of Earth’s axis allows for ice ages Milankoitch Cycle: Earth orbits in an elliptical around the sun

o Helps to define glacial periods 1300-1850 Europe and the world was experiencing a mini Ice Age;

then the industrial revolution took place around o people started measuring CO2 in the atmosphere and noticed

a warming 1970s: burning so many fossil fuels isn’t a good thing

Geologic Timescale: Earth goes through warm periods and cold periods and warm periods and cold periods

a lot hotter in the tertiary period and that was a very warm period of time

Weather vs. Climate?Weather – atmospheric conditions at a specific point in timeClimate – atmospheric conditions of a region over a long period of time UNDERSTAND:

If a species overshoots its carrying capacity, it will start to degrade its environment, and then you will decrease the carrying capacity of the species

- Since Industrial Revolution, exponential increase of amount of CO2 CO2 closely correlates with temperature Use ice sheets and capture bubbles of air to measure these blocks

of ancient air and find out the temperature of the past Ice is melting! So lots of our data is disappearing

Earth’s Climate has warmed over the past century Has warmed by 0.74 degrees Celcius Will continue to warm and warm a lot faster

Mean Annual Temperature:o The majority of the warming is happening in the northern

hemisphereWATCH: Changing Ice in free time

Minimum temperatures have risen twice as fast as maximum More rain, but in places that already has a lot of rain

Ocean Temperature Change Ocean is a place to absorb heat Good at absorbing heat; ocean is good at moderating temperature

and keeping a constant climate if you live by the ocean We are seeing a heating of the ocean all the way up to 3000 feet These oceans are expanding and rising

Looking at satellite pictures: Warming of ocean surface is largest over the artic ocean Global average heat content of the ocean is starting to increase

Rising Sea Levels Warming causes seawater to expand, raising the sea level Water is most dense at 4 degrees and starts to expand as it gets

warmer and warmer A huge amount of energy is entering the ocean and a lot of water is

expanding = seawater expands- We’re seeing more flood planes, surges of storms, hurricane Katrina and Sandy- a lot of insurance companies are pushing to be more careful- global average sea level rises – can really see it riseClimate refugees from small island communities

Sea level rises = one of the most immediate effects, and see a lot more drought

Methanogens Methane = important greenhouse grass, locked in oceans and

permafrost Siberia looks like its warming

o Can make methane to get energy and when snow melts you release methane and when you open the permafrost it can explode

If oceans continue to warm especially to lower areas, the bottom has a lot of methane and methanogens and if they’re liberated so the ocean will burp

What we’re seeing right now: Precipitation = can see statistical significance in trends and

changes of precipitation Can see where you’re getting a lot less rain and a lot more rain Some organisms are more susceptible than other organisms to

climate changeso Cold-blood animals will be more susceptible, and the ones in

the warmer regions; they live closer to their tolerances Looking back at Ice Age: very large animals back then

Warm blooded animals = animal body size increase to a decreasing temperature; more efficient to be smaller when its warmer

This is good since we’re fragmenting the environment so much Expect to see more small organisms on planet

Ectoderms: Metabolic activity increases exponentially with temperature Optional temperature where species do very well; also a place

where they can’t survive Where is the point where you wont see those species and how close

are they to this pointThermal Tolerance

Porcelain crab: heat up the temperature and find out where 50% of them die = LT50

Then they look at maximum habitat temperature is You want your LT50 to be well above maximum temperature is If you’re below you’re maximum temperature you are in trouble

Terrestrial Species’ Response to CCimpacts on terrestrial plant species are more complicated

Tree Growth: what is happening to the treeso Plants are the base of the food systemo Noticing an increase in the length of the growing season;

gives trees a longer time to grow in Eastern Long America In Western Long America = a lot of drought so plants can’t grow Arctic and West = not as much growth

However, increase in vegetation in the Arctic A lot of shrubs growing Grasslands are doing better than forests

Phenology – timing of seasonal activityMany areas have changes in migration

Change in hibernation, reproduction, etc Earlier egg laying date Birds then came to England earlier and left earlier

Meta Analysis: 203 species of animals showing amphibians showing the greatest shift in reproduction time

in an other group buttlerflies emerged quicker than their food source

watch podcast 10-10:!5Arctic Fox v Red FoxSpecies that was once limited where they could roam has no expanded; artic fox is similar to red fox and red fox was limited and couldn’t expand to arctic frost but can no do it since its warmer nowPlant community and CC

A lot more losers than winners Arizona mountains = saw temperature was increasing and rainfall

was decreasing More species becoming more limited

Ocean Systems and CC Zooplankton and phytoplankton = they are the base of the food

chain, if bad things happen it will ripple its way through the entire food chain

Warmer species of zooplankton would expand to the arctic regions and colder groups retreating more and more

WHY SHOULD WE CARE? Very important food species to us will start to lose their habitat and

warmer species are moving to their habitat Cod is on the verge of collapse Need to take a step back and look at things globally Net primary productivity – the carbon stored in plants that other

organisms can eat Maybe we’ll get more plant growth

o Did the study again and it was worseAre humans to blame for CC?General circulation models:

Try and map the present and see what’s going to happen in the future We have very large ranges because some people are more

conservative with their models

Not seeing these extremists but people are modeling what happens if we get a pulse shift

If permafrost all melts in the ocean and we get a pulse Last glacial maximum had decrease 5 degrees Celsius

Start to have mild winter: insects will have some problems Won’t kill back some species that grow very quickly May be more storms, increase in snow fall, and greater drought Because it is not happening evenly over the world; dry getting drier

and wet getting wetterDebate: hurricanes may get biggerUncertainty:

We don’t know the process of how species are currently distributed and abundantly distributed

Don’t know how much humans will change the environment Don’t know what the climate is exactly going to do

International Tundra Experiment: International collaboration: requiring humans to work together to

tackle difficult topics Have similar types of test so data can overlap and do meta-data

analysis to try and figure out what is going on globally Showing: increase height and cover of deciduous grass and shrubs

o Decrease cover of mosses and lichenso Definitely decrease in species diversity!!!

Network of Ecosystem Warming Studies: Above ground NPP; looking at soil conditions, etc Findings: soil respiration rates increase by 20%; net nitrogen

mineralization organic N N2 rates inc by 46%, NPP increase by 19%

o Releasing more CO2 into the atmosphereFuture direction:

It’s likely that plants will start to move and we can project where plants and animals are moving

However, this isn’t always true; sometimes they just climatize Looked at 134 tree species of U.S. and saw the sugar maples and in

high models will maybe lose the tree Climate scenario: tree richness will increase in Canada but drought

in Californiao We grow most of USA food in California

50% of carbon released through human activities remain in the atmosphere the remaining percent is taken up in oceans, but taken up by

carbonic acid and becoming more acidity, dissolving the shells of some marine animals

terrestrial plants = growing more plantsOne of the models:

In the next 100 years, are we going to see more NPP in the ecosystem; at first we did but 10 years later we saw less in recent studies, what will happen in the future?

We can have a negative feedback loop, BUT if plants don’t respond as well then we’d have a positive feedback loop

Results show great uncertainty in the predicted patterns of carbon exchange Projections can either be way off or on point Main result of the models: 3/5 showed NPP would decrease

Can we do anything about Climate Change and should we?

12/3/15 1:30 AM

12/3/15 1:30 AM