Climate Change

What is global change?

All planetary scale changes in the earth across all systems

What are the three major earth systems that are affected by global change?

• Climate change (includes temperature, precipitation)

• Geochemical (includes C, N, P cycling)

• Biota (includes organisms, ecosystems, biodiversity)

Is global change just warming?

No, it includes much more than temperature increase

• Some areas getting cooler, drier, wetter

Is global change just CO2?

No, it includes multiple interacting factors (nutrients, land use, biodiversity)

Why is the current global change unique?

• It has caused the fastest changes in history

• Most intense changes in history

 

What is happening to atmospheric CO2 levels

increasing over time (upward trend)

What happens to the CO2 level during the summer?

Since theres more photosynthesis, the CO2 level decrease as a result

What happens to the CO2 level during the winter?

Since theres more respiration, the CO2 level increases as a result

What are geochemical cycles?

Fluxes of elements through earth pools

What are the 3 types of carbon isopotes?

• C12 (most common)

  • 98.9% of the atmosphere

• C13 (the most stable)

  • makes up 1.1% of the atmosphere)

• C14 (most radioactive)

  • Used Radioactive C dating

  • <0.00001% atm

How does atmospheric C-14 decrease?

as it gets absorbed by oceans and biosphere

What does a C-14 spike tell us?

that elements move quickly between pools (atmospheres, oceans, biospheres)

What does a decrease in the C-13 ; C-12 ratio indicate?

It indicates that more carbon is coming from plants/fossil fuels

What does a decrease in the C-14 ; C-12 ratio indicate?

It indicates that carbon is coming from old source such as fossil fuels

What does a decrease in the C-13 ; C-14 ratio indicate?

It indicates that extra CO2 is coming from burning fossil fuels

How are winter temperatures changing?

As minimum temperatures are rising faster than maximums

What happens as we get warmer winters?

There is less winter mortality of forest pests

Why do warmer winters increase pest populations?

because fewer individuals are dying from the cold, resulting in more of them surviving and the pest population increasing

Why does reduced winter mortality of pests affect ecosystems?

• It leads to

  • Increased herbivory

  • Forest damage

  • Altered community structure

How does global change affect disturbance?

it increases both the frequency and intensity of disturbances

What are the three main strategies to manage forest health under climate change?

• Assisted population migration

• Assisted range expansion

• Assisted species migration

What is assisted population migration?

The movement of individuals within their current historical range

• Which helps populations adapt to local climate shifts

What is assisted range expansion?

the movement of species just beyond its current range boundary

• Which helps species track shifting climates as suitable habitat moves

What is assisted species migration?

the movement of species far outside its historical range

• But is controversial due to the risk of invasive species and unpredictable ecosystem effects

Why are the three main strategies to manage forest health needed under climate change?

Because climate is shifting faster than species can naturally migrate