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The Precautionary Principle IB Topic 5. 2
The precautionary principle o The Intergovernmental Panel on Climate Change (IPCC) n n n Created in 1988 Find out if human activities have an impact on climate What do you think they found?
IPCC Findings o 2007; their 4 th report showed that: n Global temperatures are increasing n Global warming is not a hypothesis but a confirmed reality n There is a 90% chance increasing temperatures are due to production of greenhouse gases by human activity p Less than 5% chance due to natural causes n Within the next 100 years, sea level is expected to rise between 18 cm-59 cm n Likely severe weather will increase p Heat waves, droughts, heavy rains
Warning signs lead experts to evoke the precautionary principle o Ethical theory o Action should be taken to prevent harm even if there is not sufficient data to prove the activity will have severe negative consequences o 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 … o Industries and consumers tend to proceed with their activities until it’s obvious harm is being done o With irrefutable proof, activity is usually taken to reduce the activity in question
Example o The use of DDT n pesticide o Prohibited in North America o Proven to accumulate in ecosystems o Reduce populations of birds of prey n Bald eagle
Evaluating the principle o Tenets of the precautionary principle say preventative action should be taken now n n Reduce greenhouse emissions/gas Before it’s too late o Also say those who wish to continue producing excess greenhouse gases n Should prove that there are no harmful effects before continuing
The other side of the argument o Farmers, manufacturers, transportation providers, among others, wonder: n 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, o Unless preventative measures are taken across the board by countries world wide n n There will always be polluting competitors who can offer products at a lower price Capital vs. ecological measures o Well informed consumers? n Choose eco-friendly products n What message does this send to companies? n Are we seeing this today?
Turn and talk o Suppose you want to buy a particular product. You find what you want and the labeling says it is produced using ecofriendly 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 o Is money spent now on protective measures wasted money? o Is it less expensive to prevent a problem than to fix it? n n In most cases yes We see this in health care, too p Cheaper to screen for a disease, educate people … than to pay for treatment & repercussions o o Obesity … ~$100 billion is spent annually on obesity related issues in the US
Human impact on Arctic ecosystems o Parts of North America, Greenland, Iceland, Norway, and Russia o Changes: n n n More ice melting/year Less snow & more frozen rain Mosquitoes!? Woody shrubs warmer soil Robins p New species = new pathogens
Consequences in the Arctic o Changing ecosystems n n n 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 o Long swims – need ice to rest … o Rely on seals as main food source o Hunting techniques: to stand on ice near a hole and wait for seals to come up for air o Less ice … what happens to this technique? o Less food n Cub population has decreased by 10% over the past 20 years
In conclusion o Carbon is a super important element to the biosphere n n Must be recycled Levels are affected by: p Photosynthesis p Respiration p Combustion p Feeding p Decomposition o Earth’s natural greenhouse is essential for life o It’s just intensifying n Human activity n Carbon dioxide, methane
For your test tomorrow o 5. 2 o Draw and label the carbon cycle n How does carbon enter? Leave? o Analyze changes in CO 2 concentration o Explain the greenhouse effect o Outline the precautionary principle