Lecture 4 -- The Physical Environment: Water and Climate Change

Question 1

What are examples of “natural forcings” that can cause changes in global climate?

Answer 1

Volcanic eruption, variations in solar radiation, variations in ocean circulation.

Question 2

Why did the Intergovernmental Panel on Climate Change (IPCC) come up with different scenarios of carbon dioxide emissions?

Answer 2

To model different siutations based what actions people might (or might not) take and how severe the results would be.

Question 3

he three main scenarios that people use to model future climate are the A2, A1B and B1. What are the major differences between the three, in terms of assumptions about the decisions that humanity makes over the next century?

Answer 3

A2: humans lower some of their emissions and make some lifestyle changes. This will cause our CO2 emissions to rise for a little more, and then start to decrease gradually. Temperatures overall increase 3-5 F degrees average.
A1B: humans continue to increase their CO2 emissions causeing our emissions to increase exponentially.Temperatures increase up to 6 F degrees
B1: humans completely cut off fossil fuels and reduce CO2 emissions very quickly over the next century, returning our emissions and concentrations to a lower level. Temperatures overall increase 2-3 F degrees.

Question 4

Over the Arctic, in what season is the greatest change in temperature expected due to climate change?

Answer 4

Winter because there will be more sunlight facing the Arctic.

Question 5

Where do surface temperatures change the most, over the ocean or over land? What part of the U.S. is expected to see the biggest summer temperature change?

Answer 5

On average, there will be greater temperature changes over land. In the western part of the Midwest, there will be the most summer temperature changes with a 4 F degree increase.

Question 6

How is precipitation on the west coast expected to change in the winter and summer?

Answer 6

Percipitation is going to get more frequent and extreme during the winter. This means that we will have wet winters and very dry summers due to less snowmelt runoff. THATS WHAT SHE SAID DA DUM TSHH

Question 7

• the average temperature in the NW in the year 2100, for the B1 scenario (the optimistic, we get our act together quickly scenario), is higher than the historic average, but still within the normal range of variability of historic temperatures.

Answer 7

False

Question 8

• Average temperature is expected to increase in all four seasons of the year.

Answer 8

True

Question 9

• Average precipitation is expected to increase in all four seasons of the year.

Answer 9

True thats what she said.Just stop

Question 10

How is the hydrograph (seasonal flow regime) in the Skagit River expected to change in the future? Why?

Answer 10

Peak flows are expected to be larger and earlier. Winter precipitation that would have been snow histroically, slowly melting into rivers in summer, will be rain and run into rivers immediately and in great amounts.

Question 11

What factors contribute to increased flooding in the future?

Answer 11

Warmer temperatures increase contributing basin area during storm (can change the seasonal timing of flooding)
Increasing winter precipitation increases the storm intensity

Question 12

What does it mean that the effective contributing basin area is increasing?

Answer 12

The freezing elevation is rising which means that there is more basin area producing runoff during winter storms

Question 13

How does a changing snow line (freezing level) affect flooding?

Answer 13

it will increase the size of floods

Question 14

How will average runoff in the Nooksack basin change by the 2020’s, for the summer and winter?

Answer 14

average runoff in the Nooksack basin will decrease by 27% in the summer months by the 2020’s and increase by 15% in the winter months

Question 15

What are some different ways in which climate change may increase sediment production from Puget Sound rivers?

Answer 15

Increasing peak flows, retreating glaciers, declining snow pack, and increased fire frequencies will increase sediment production

Question 16

What is a sediment rating curve for a river?

Answer 16

The amount of suspended sediment

Shows amount of suspended sediment on y-axis and river flow on x-axis

Question 17

What are some ecological implications of climate change impacts on river flow regimes and sediment loads? How will more frequent large floods in the winter affect rivers and the things that live in them? How will lower low flows in the summer affect rivers and things that live in them?

Answer 17

Shifting river channels – more sediment, more water Riparian buffers – more erosion, more sediment into river More sed in estuaries – may mean more dredging for shipping Faster flow, more channel scour Increased turbidity Salinity – lower low flows lower salinity Less water for drinking (where it comes from river) Less water for irrigation Faster flow, more dissolve O2 in water Industry in floodway more likely to contribute pollutants Could affect estuarine mixing zone – how the salt/fresh meet/mix - balance of predator/disease in estuaries Damage to infrastructure/roads Water treatment infrastructure…sediment overloads Organisms near waterfalls/etc dependant on spray etc. Less flood conveyance capacity with sediment build up