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Jenni MacLean
Jenni MacLean
This unit is a culminating look at how the actions of humans can have global impacts. By understanding how our actions can alter environments and the consequences they have on species, we can begin to develop a plan for change. We will explore cases of countries coming together and having great success in preserving Earth's natural resources, as well as times when humans have caused irreparable harm. Some of the topics include global climate change, altering the ocean's temperature and pH, and biodiversity loss. Overall this unit provides a look into the vast impact humans can have and offers avenues for hope and change.
The layer of ozone is vital for life on Earth because it absorbs UV radiation from the sun. A molecule of O3 is broken into O2 and O when hit by UV rays. It then quickly reforms into an O3 and is ready to do it again.
Humans altered this process by using Chlorofluorocarbons (CFCs). CFCs are useful as propellants in many products (think of anything that comes out of a spray can). They are a highly stable compound that can make it to the stratosphere unchanged. Once in the stratosphere, they are broken apart by UV radiation, and the chlorine (Cl) is free to bond with oxygen (O) atoms making them unable to reform ozone (O3). This ongoing process is a huge reason why the ozone layer is depleting.
So that sounds scary- and it is! When UV-A and UV-B rays come into contact with animals, they can cause skin cancer and cataracts. But the good news is, we fixed it! Well, kind of. In 1989 countries gathered together to write and sign the Montreal Protocol. This legislation encouraged the phasing out of ozone-damaging chemicals like CFCs. It was widely signed and implemented in industrialized countries. As a result, we have seen substantial reductions in ozone depletion and a reduction of the 'ozone hole.' (Note: It takes a long time for CFCs to reach the stratosphere, so it will take around 100 years to see the effect of reducing their use entirely.)
So here it is, the big topic in APES, climate change. To understand what's going on, we first have to look at the greenhouse effect, which is the naturally occurring process by which heat from solar energy is trapped next to the Earth. Certain gasses have a higher thermal retention property than others, which means they can hold on to heat longer. For example, you know how a coffee mug☕ is good at keeping your coffee warm, while a glass cup 🍷 would let the coffee cool down quickly? It is the same concept - just with gasses.
The primary greenhouse gasses (or gasses that trap heat) are Carbon Dioxide, Methane, Water vapor, Nitrous oxide, and Chlorofluorocarbons (CFCs). Humans increase the amount of these gasses in the troposphere and, in turn, increase the potential for heat to be trapt, thus causing an increase in global average temperatures.
Here is a chart looking at the primary gases, their sources, concentration, and global warming potential (GWP). The GWP is a value of the thermal retention property compared to carbon dioxide, or how much heat it can hold compared to CO2.
CO2 (aq) + H2O ⇌ H2CO3 ⇌ HCO3− + H+ ⇌ CO32− + 2 H+
The increasing acidity creates problems for organisms that make their bodies out of calcified shells like corals, algae, and shellfish 🐌. Their bodies dissolve, or they are unable to grow as they typically would. This problem expands its impact when we look at organisms like pteropods, which are in decline and are a major basis of the food chain.
In general, specialist and K-selected organisms are more susceptible to extinction, where generalist and r selected are more likely to adapt. However, human actions tend to target one species over another. The abbreviation HIPPCO is an excellent way to remember the major reasons for species decline. HIPPCO stands for: habitat destruction, invasive species, population growth, pollution, climate change, and over-exploitation..
1973 - The Endangered Species Act:
United States Regulation created this act to protect endangered and threatened species, designed to preserve habitats to protect organisms from extinction.
1987 - The Montreal Protocol:
The Montreal Protocol is an international agreement designed to phase out the production of chemicals responsible for ozone depletion.
1992 - The Kyoto Protocol:
The Kyoto Protocol is an international agreement to reduce greenhouse gasses.
1996 - National Invasive Species Act (NISA):
A United States federal law intended to prevent invasive species from entering inland waters through ballast water carried by ships.
2016 - The Paris Agreement:
The Paris Agreement is an international agreement within the United Nations Framework Convention on Climate Change (UNFCCC) dealing with greenhouse-gas-emissions mitigation. November 2019, as soon as it was legally possible, the U.S. submitted a formal notice of withdrawal.
🎥 Watch: AP Environmental Science Streams
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Jenni MacLean
Jenni MacLean
This unit is a culminating look at how the actions of humans can have global impacts. By understanding how our actions can alter environments and the consequences they have on species, we can begin to develop a plan for change. We will explore cases of countries coming together and having great success in preserving Earth's natural resources, as well as times when humans have caused irreparable harm. Some of the topics include global climate change, altering the ocean's temperature and pH, and biodiversity loss. Overall this unit provides a look into the vast impact humans can have and offers avenues for hope and change.
The layer of ozone is vital for life on Earth because it absorbs UV radiation from the sun. A molecule of O3 is broken into O2 and O when hit by UV rays. It then quickly reforms into an O3 and is ready to do it again.
Humans altered this process by using Chlorofluorocarbons (CFCs). CFCs are useful as propellants in many products (think of anything that comes out of a spray can). They are a highly stable compound that can make it to the stratosphere unchanged. Once in the stratosphere, they are broken apart by UV radiation, and the chlorine (Cl) is free to bond with oxygen (O) atoms making them unable to reform ozone (O3). This ongoing process is a huge reason why the ozone layer is depleting.
So that sounds scary- and it is! When UV-A and UV-B rays come into contact with animals, they can cause skin cancer and cataracts. But the good news is, we fixed it! Well, kind of. In 1989 countries gathered together to write and sign the Montreal Protocol. This legislation encouraged the phasing out of ozone-damaging chemicals like CFCs. It was widely signed and implemented in industrialized countries. As a result, we have seen substantial reductions in ozone depletion and a reduction of the 'ozone hole.' (Note: It takes a long time for CFCs to reach the stratosphere, so it will take around 100 years to see the effect of reducing their use entirely.)
So here it is, the big topic in APES, climate change. To understand what's going on, we first have to look at the greenhouse effect, which is the naturally occurring process by which heat from solar energy is trapped next to the Earth. Certain gasses have a higher thermal retention property than others, which means they can hold on to heat longer. For example, you know how a coffee mug☕ is good at keeping your coffee warm, while a glass cup 🍷 would let the coffee cool down quickly? It is the same concept - just with gasses.
The primary greenhouse gasses (or gasses that trap heat) are Carbon Dioxide, Methane, Water vapor, Nitrous oxide, and Chlorofluorocarbons (CFCs). Humans increase the amount of these gasses in the troposphere and, in turn, increase the potential for heat to be trapt, thus causing an increase in global average temperatures.
Here is a chart looking at the primary gases, their sources, concentration, and global warming potential (GWP). The GWP is a value of the thermal retention property compared to carbon dioxide, or how much heat it can hold compared to CO2.
CO2 (aq) + H2O ⇌ H2CO3 ⇌ HCO3− + H+ ⇌ CO32− + 2 H+
The increasing acidity creates problems for organisms that make their bodies out of calcified shells like corals, algae, and shellfish 🐌. Their bodies dissolve, or they are unable to grow as they typically would. This problem expands its impact when we look at organisms like pteropods, which are in decline and are a major basis of the food chain.
In general, specialist and K-selected organisms are more susceptible to extinction, where generalist and r selected are more likely to adapt. However, human actions tend to target one species over another. The abbreviation HIPPCO is an excellent way to remember the major reasons for species decline. HIPPCO stands for: habitat destruction, invasive species, population growth, pollution, climate change, and over-exploitation..
1973 - The Endangered Species Act:
United States Regulation created this act to protect endangered and threatened species, designed to preserve habitats to protect organisms from extinction.
1987 - The Montreal Protocol:
The Montreal Protocol is an international agreement designed to phase out the production of chemicals responsible for ozone depletion.
1992 - The Kyoto Protocol:
The Kyoto Protocol is an international agreement to reduce greenhouse gasses.
1996 - National Invasive Species Act (NISA):
A United States federal law intended to prevent invasive species from entering inland waters through ballast water carried by ships.
2016 - The Paris Agreement:
The Paris Agreement is an international agreement within the United Nations Framework Convention on Climate Change (UNFCCC) dealing with greenhouse-gas-emissions mitigation. November 2019, as soon as it was legally possible, the U.S. submitted a formal notice of withdrawal.
🎥 Watch: AP Environmental Science Streams
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