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