Unit 9: Global Change Flashcards
(17 cards)
What phenomena cause the climate to change naturally?
volcanic eruptions
el nino and la nina
changes in solar radiation/the sun
What are the anthropogenic causes of climate change?
- combustions engines (releases CO2, greenhouse gas)
- industrial revolution led to the creation of a lot of factories which emit greenhouse gasses (CO2, methane/CH4)
- deforestation causes less carbon sinks
- livestock (methane, greenhouse gas)
Kyoto Protocol of 1997
- global agreement that first attempted to control G.H.G emissions
- Notable because the United States and China never ratified/adopted it.
- Now replaced by the Paris Agreement!
Effects of Climate Change:
- Changes in sea levels: Sea levels rise due to glaciers melting and thermal expansion of the oceans, this causes more coastal flooding
- Changes in weather patterns: major weather events (hurricanes, floods) are more extreme (more rain, snow, etc…) and more heat waves and droughts (more intensive as well)
- ## Changes in agricultural practices: growing seasons altered and crops may have less yield and are less nutritious
The Albedo Effect and Positive Feeback Loop
- “Albedo” is a term used to measure (high vs low) the reflectivity of a surface (ice has higher albedo vs water)
- less ice/snow -> more ocean water -> more heat absorbed -> more melting (hence the positive feedback loop
Ocean Acidification
- Marine shells (and coral!) are made of calcium carbonate (CaCO3)
- hydrogen ions (H+) combine with carbonate ions (CO3-2) to form carbonic acid (H2CO3) which takes away carbon available for the shells
- so more energy is is spent building shells vs finding food) -> trophic cascades -> biodiversity declines
- the chemical equation for ocean acidification:
CO2(g) + H2O(l) → 2H+(aq) + CO3-2(aq)
Ocean Warming
- causing coral bleaching, which occurs when the loss of algae within corals cause the corals to bleach white
- Some corals can recover but too many die as a result.
- Not due to thermal pollution (factories dumping warm water), it is due to greenhouse gasses trapping heat in the atmosphere
- the color the coral comes from symbiont (the algae)
- if there is too much heat or light energy entering the photosystem, damage occurs inside the cell
- damage leads to symbiont ejection -> coral spit out the symbiont -> bleaching
symbionts provide energy to coral, so missing symbionts lead to coral death
Ozone Depletion
- means that the ozone layer IN THE STRATOSPHERE is getting thinner
- the rate of ozone depletion > the rate of ozone formation (remember the ozone layer is dynamic and O3 is always being formed and breaking down)
- The ozone layer depletes more quickly when:
- Using CFCs (chlorofluorocarbons) - anthropogenic
- Melting of ice crystals in atmosphere at the beginning of the antarctic spring (August to November)
Chlorofluorocarbons (CFCs)
- Refrigerants and air conditioners
- Aerosol sprays/propellants
- “Blowing agents” for foams and packing materials
- greenhouse gas caused by only anthropogenic actions
How do CFCs Cause Stratospheric Ozone Depletion
- UV causes a chlorine atom to break away from the CFC molecule
- the free chlorine atom hits an ozone molecule
- the chlorine atom pulls one ozygen away
- a free oxygen atom hits the chlorine monoxide molecule
- the result is another free chlorine atom
- free chlorine continue to deplete ozone in the stratosphere
The Montreal Protocol (1987)
- Phased out production & use of CFCs by 1996, and of HCFCs by 2030.
- As a result, the ozone layer is on the road to recovery!
HCFCs (hydrochlorofluorocarbons)
- Greenhouse gas (exclusively anthropogenic)
- Ozone-depleting chemical (less impactful than CFCs)
- Comes from a variety of industrial processes
Melting of Ice Crystals in the Atmosphere
- During the Antarctic winters, the air in the polar vortex gets so cold that ice crystals form.
- Chlorine atoms accumulate in these ice crystals!
- When springtime comes, those ice crystals melt, and the Cl atoms are liberated to break down the O3 molecules
Environmental Impacts of a Thinning Ozone Layer
Effects on plants:
- Disrupts physiological and developmental processes → photosynthesis is disrupted → productivity in ecosystems declines
Effects on marine ecosystems:
- phytoplankton → they die and productivity of the ecosystem declines
*Changes functionality of biogeochemical cycles, too!
Human Health Impacts of a Thinning Ozone Layer
- Higher incidences of melanoma and skin cancers
- Higher incidences of cataracts
- High incidences of weaker immune responses
Introduced Species
- They outcompete native species for resources!
- often generalists, r-selected species
- They have lots of offspring in short amounts of time
- They reach reproductive maturation early in their life spans
What factors impact biological diversity?
HIPPCO
H: Habitat destruction
- removal/change in habitats is a “stressor” that could wipe out organisms or species, reducing the gene pool → biodiversity declines
I: Invasive Species
- outcompete native species over limited resources; can displace native species due to rapid reproductive strategies → biodiversity decreases
P: Pollution
- alters the chemistry of the air, water, and soil where species live; causes them to die off → biodiversity decreases
P: Population
- A (growing) population leads to more resources used (and amplifies the other factors listed)
C: Climate Change
- changes in Earth’s systems forces species to adjust to new temperature & pH conditions (more quickly than they’re able) → biodiversity declines
O: Overharvesting
- exhausting a finite resources because it is getting used in an unsustainable fashion
ex: overfishing, overhunting
- Reduces the number of organisms left to survive → biodiversity declines
