Lecture 2 - Global Risks and Planetary Boundaries Flashcards
(49 cards)
Planet definition
an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity
What are the two external threats to our planet?
The sun engulfing the earth
Meteors
Why is it unlikely that a meteor poses significant danger to the Earth?
They’re not very frequent anymore, and impact energy would have to be greater than gravity to stop earth re-accreting
What does the biosphere encompass?
All living creatures and the relationships between all those living creatures and relationships between those living creatures and non-living parts of the Earth
External threats to the biosphere?
Meteorite impacts
Gamma-ray bursts
What is the biggest threat to the biosphere?
Meteorite
Internal threats to the biosphere?
Core/mantle convection
Rapid climate change
Biosphere imbalance
What is biosphere imbalance?
Something happening within the biosphere that threatens itself - e.g. one species over-evolving
What is the current biosphere threat?
Humans
How many animals would go extinct if there was an 8-10 degree temperature rise?
more than 80%
External threats to human society?
Planetary threats
Biosphere threats
Internal threats to human society
Ones of our own making
How has the rate of change of population and increase in urban population changed and what has this caused?
increased significantly since the 1950s, causing a consecutive massive increase in our use of resources.
What other effects does a rapidly increasing population have?
massive increases in other things, such as GDP, FDI, energy use, water use and paper production
What was the change in CO2 levels like since the industrial revolution?
Steady increase
How has CO2 and nitrous oxides levels changed since the 1950s?
Increased rapidly
What have humans always had?
An impact on the environment
What is the problem with advancements in medicine?
There is lower death rates, but birth rate doesn’t decrease. Therefore, the population explodes
When was the peak of population growth and what was it?
1962 - 2.2% per year
What is the next challenge for the human race?
dealing with our population growth without ruining our planet
How do we believe population growth will change in the next century?
We believe that population growth will continuously decline to 0 over the next century
What are planetary boundaries?
A science-based analysis of the risks that things that we are doing would destabilize the earth system at a planetary level. Not just local, but changes that will affect all of us
What are the two biggest planetary based boundaries?
biochemical flows and genetic diversity
What are the two main biochemical flows, and what is the problem?
Nitrogen and phosphorous are used in fertilizers, which results in them leaking into oceans and waterways and causing major problems such as algal blooms
