The Precautionary Principle IB Topic 5.2. The precautionary principle The Intergovernmental Panel...
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Transcript of The Precautionary Principle IB Topic 5.2. The precautionary principle The Intergovernmental Panel...
The Precautionary Principle
IB Topic 5.2
The precautionary principle
The Intergovernmental Panel on Climate Change (IPCC) Created in 1988 Find out if human activities have an impact
on climate What do you think they found?
IPCC Findings
2007; their 4th report showed that: Global temperatures are increasing Global warming is not a hypothesis but a confirmed
reality There is a 90% chance increasing temperatures
are due to production of greenhouse gases by human activity
Less than 5% chance due to natural causes Within the next 100 years, sea level is expected to
rise between 18 cm-59 cm Likely severe weather will increase
Heat waves, droughts, heavy rains
Warning signs lead experts to evoke the precautionary principle
Ethical theory Action should be taken to prevent harm
even if there is not sufficient data to prove the activity will have severe negative consequences
Also, if people choose to engage in an activity that may cause changes in the environment, they must first prove it will do no harm
Without the precautionary principle …
Industries and consumers tend to proceed with their activities until it’s obvious harm is being done
With irrefutable proof, activity is usually taken to reduce the activity in question
Example
The use of DDT pesticide
Prohibited in North America
Proven to accumulate in ecosystems
Reduce populations of birds of prey Bald eagle
Evaluating the principle
Tenets of the precautionary principle say preventative action should be taken now Reduce greenhouse emissions/gas Before it’s too late
Also say those who wish to continue producing excess greenhouse gases Should prove that there are no harmful
effects before continuing
The other side of the argument
Farmers, manufacturers, transportation providers, among others, wonder: Why invest $ in new techniques to reduce
greenhouse emissions if scientists are not 100% sure how an enhanced greenhouse effect is going to be harmful to the environment
So,
Unless preventative measures are taken across the board by countries world wide There will always be polluting competitors
who can offer products at a lower price Capital vs. ecological measures
Well informed consumers? Choose eco-friendly products What message does this send to
companies? Are we seeing this today?
Turn and talk
Suppose you want to buy a particular product. You find what you want and the labeling says it is produced using eco-friendly techniques. But it costs 25% more than a similar product which is not eco-friendly. Which would you buy? Why?
Prevention is better than cure
Is money spent now on protective measures wasted money?
Is it less expensive to prevent a problem than to fix it? In most cases yes We see this in health care, too
Cheaper to screen for a disease, educate people … than to pay for treatment & repercussions
Obesity … ~$100 billion is spent annually on obesity
related issues in the US
Human impact on Arctic ecosystems Parts of North America, Greenland,
Iceland, Norway, and Russia Changes:
More ice melting/year Less snow & more frozen rain Mosquitoes!? Woody shrubs warmer soil Robins
New species = new pathogens
Consequences in the Arctic
Changing ecosystems Intact ice allow algae to grow (attach to
underside, transparent to light, allow for photosynthesis)
Ice melting – less surface to stick to Less algae (producers) … what happens to
other trophic levels?
And the polar bears
Long swims – need ice to rest … Rely on seals as main food source Hunting techniques: to stand on ice near a hole
and wait for seals to come up for air Less ice … what happens to this technique? Less food
Cub population has decreased by 10% over the past 20 years
In conclusion Carbon is a super important element to the
biosphere Must be recycled Levels are affected by:
Photosynthesis Respiration Combustion Feeding Decomposition
Earth’s natural greenhouse is essential for life It’s just intensifying
Human activity Carbon dioxide, methane
For your test tomorrow
5.2 Draw and label the carbon cycle
How does carbon enter? Leave?
Analyze changes in CO2 concentration
Explain the greenhouse effect Outline the precautionary principle