What are the problems with the current changes in ecosystems?
The rate and scale at which humans modify them has drastically increased
What are some examples of changes humans have brought to ecosystems?
- Habitat modification
- Nutrient and chemical flows (fertilizers, heavy metals)
- Moving species around the world
- Changing the atmosphere
Define
Anthropogenic changes
Major changes to populations, communities and
ecosystems caused by human activities
Not limited to climate change
Define
Global Change Biology
The study of rapid and ongoing anthropogenic
changes that have “global scale” consequences
Why is it hard to predict effects of
human actions on the world?
- Multiple drivers and natural variation
- Lagged effects
- Feedbacks
Give an example of positive feedback
Added CO2 causes the air to absorb more heat, heat creates water vapour, water vapour then traps more heat
Give an example of negative feedback
- More vapour creates more clouds
- Clouds reflect light
- Air absorbs less heat
How are we changing the environment?
- Climate change
- Land-use change
- Nutrient cycling
- Chemicals added to the environment
Describe the lags and feedbacks affecting climate change
- Lags: ocean heating
- Feedbacks: formation of water vapour, emission of CO2 from biomes, changes in ocean circulation
Describe the lags and feedbacks affecting land-use change
- Lags: recovery of plants after the last ice age, extinction debts
- Feedbacks: Fire, water infiltration
Describe the lags and feedbacks affecting nutrient cycling
- Lags: plants and algae take time to increase in population, nutrients can cycle in ecosystems for a long time
- Feedbacks: eutrophication can lower oxygen and kill predators (positive); algae/plants dying can remove nutrients
Describe
The effects of chemicals added to the environment
- Pharmaceutical drugs enter freshwater ecosystems through humans sewage and agricultural runoff
Describe
Acid precipitation
- Creation of acid precipitation, contains sulphuric acid and nitric acid from the burning of wood and fossil fuels
- Air pollution from one region can result in acid precipitation downwind
Define
Mitigation
Slowing rates of change/reducing the magnitude of overall change, to give ecosystems and species time to adapt
Define
Adaptation
Finding ways to help ecosystems and people adapt to changes
