PLANETARY BOUNDARY

What is the difference between a planetary boundary and a global threshold?

a planetary boundary is defined to provide a buffer zone or response time before a global threshold is crossed.

resilience

the ability for an ecosystem to tolerate perturbations or shocks and continue to function under changing abiotic conditions.

How many planetary boundaries have been crossed?

4

Which of the 9 planetary boundaries have. been crossed?

climate change, biogeochemical flows, land system change and biosphere integrity

What factors make up the "quadruple squeeze" of pressure on the earth system?

population, climate change, ecosystem decline, surprise

what does the term "surprise" mean?

means that systems can change and/or tip unpredictably. There is always some uncertainty in science

Precautionary principle

a principle based on the belief that action should be taken against a plausible environmental hazard, even if some cause-and-effect relationships are not fully established scientifically

Anthropocene era

This period is characterized by humans being the primary driver of environmental change at a planetary level.

Lithosphere

realm of rock: study of rock and physical; processes involving rock

examples of lithosphere

minerals, fossil fuels, volcanism, plate tectonics

Hydrosphere

realm of water: studied in hydrology (study of water movement and storage, quantity and quality)

Limnology

study of freshwater ecosystems

Cryosphere

A term referring to all water that is temporarily frozen in polar ice caps, snow, permafrost, and glaciers

Atmosphere

realm of air: studied in atmospheric science (including climatology, meteorology, air quality); geography

Biosphere

realm of life: studied in biology, ecology

what are the 5 earth spheres?

atmosphere, cryosphere, lithosphere, biosphere and hydrosphere

Drought for several years (what sphere caused this to happen?)

hydrosphere

heavy grass cover sprouted by a late spring rainfall

biosphere and hydrosphere

dry weather spell for seven months

atmosphere and hydrosphere

low humidity due to several wind events

atmosphere

unusual dry "fuel"

biosphere

hot gusting high wind event the day of fire with gusts of 25-35 mph

atmosphere

what are the 9 Planetary boundaries?

- Atmosphere aerosols

- Biogeochemical flows

- Biosphere integrity

- Climate change

- Fresh water use

- Land system change

- Novel entities

- Ocean acidification

- Ozone depletion

what happens when a boundary is crossed?

increases the risk of large-scale abrupt or irreversible environmental changes