Lecture 2 - Global Risks and Planetary Boundaries Flashcards
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
Do we know how serious all planetary boundaries are?
No
What was the CO2 ppm before the industrial revolution?
About 280 ppm
What is the CO2 ppm now?
410 ppm
How is the rate of change of carbon dioxide in the atmosphere changing?
It’s increasing
Why is it difficult for us to stop using fossil fuels?
They have always benefitted us in the past (almost every advancement has come from using an abundance of fossil fuels).
What must we accept about fossil fuels now?
we are now in a position where using fossil fuels results in more harm than good
What is genetic diversity quantified by?
extinction rate
What is a mass extinction?
an event where 75% or more of species are lost over a relatively short period of time
What % of risk experts said that economic confrontations and domestic political polarization would be a problem in 2020?
78%
What category were the top five global risks in terms of likelihood in 2020?
Environmental
What % of wild mammals are extinct because of humans?
83%
What % of plant are extinct because of humans?
50%
What were the major predicted environmental disasters in 2020?
Climate action failure, extreme weather, biodiversity loss and natural/human made disasters
What type of problem are global pandemics?
can be classified as an environmental problem (human impact on the environment results in the spread of the disease
What does the ozone do?
Filters out UV radiation from the sun
What is the problem if we lose/break the ozone?
If it decreases, more UV radiation reaches the ground, causing cancer and damage to terrestrial and marine biological systems
How has changes to ecosystems changed in the last 50 years?
They have been more rapid than ever before
What are the main drivers for biospheric change?
food, water, and natural resources
What happens to CO2 in oceans?
Dissolves, creating carbonic acid
Why is excessive CO2 in the oceans bad?
Carbonic acid reduces the pH of surface water, changing habitat conditions
What is the problem with our water consumption right now?
We take more water out of the ground than is put in
What have forests, grasslands, wetlands and other vegetation types been converted into?
Agricultural land
What is the problem with us having excessive agricultural land?
reduces biodiversity, water resources, and the earth’s ability to absorb carbon dioxide that we emit
What does atmospheric aerosol loading affect?
climate via the hydrological cycle, and how much solar radiation is reflected/absorbed
How many people does highly polluted air kill yearly?
roughly 800,000 people
