Sem 1 Exam - Global Climate Change S2 Flashcards
Carbon Cycle in words
- Carbon enters the atmosphere as carbon dioxide from respiration and combustion
- Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis
- Animals feed on the plants, passing carbon compounds along the food chain
- Most of the carbon they consume is exhaled as CO2 formed during respiration
- These plants eventually die and release carbon
Influence of Carbon Cycle
Regulates global temp by controlling the amount of carbon in the atmosphere
Changes to the flow of carbon being evenly distributed will cause certain resovoir streams to have excess amounts –> warmer temperatures
Natural Cause 1 of CC: Solar Variation
Definition, Event, HOW causes CC
Definition: Changes in the amount of radiation emitted by the sun. A solar variation known as sunspots contribute to the intensification of CC
Event: Maunder Minimum
- During the late 17th century sunspot activity decreased dramatically where almost no sunsposts were observed during 1690 to 1715
- This created a cooling effect due to absence of solar activity
-During this time winters in Europe were longer and colder
This disruption of the Earth’s global heat budget contributed to an increase in the rate of climate change as CO2 were being emitted at increased rates. —> Photosynthesis not occurring carbon cycle also thrown off (not regulated)
Natural Cause 2 of CC: Volcanoes
Definition, Event, HOW causes CC
Volcanic activity can contribute to both warming and cooling effects
Event: Mt Tambora, 1815, Indonesia
Death toll of over 71k
Released huge amounts of suplhuric acid aerosols into the stratosphere: crops failed, glaciiers advanced down slopes
Persistent fog dimmed sunlight globally
Mt. Tambora caused global cooling effect of 3 to 3.5 degrees through mass fog which spread through the earths atmosphere: CAUSED MANY PLANTS AND ANIMALS TO GO EXTINCT
Anthropogenic Cause 1 of CC: Power Generation
Definition, Event, HOW causes CC
Largest contributor to green house gas emissions. The use of fossil fuels to generate electricity accounts for 25% global emissions
Event: Australia consumes 230 billion kwh of electrical energy per year. This primarily comes from fossil fuel combustion from things like coal: contributes to 40% of power generation
- A 500 MW coal power plant will produce 3 million tonnes of CO2 emissions per year, This contributes to increased global temps/global warming because of its circulation
Anthropogenic Cause 2 of CC: Deforestation
Definition, Event, HOW causes CC
Land cleared by humans for agricultural processes causes increased CO2
Forests are a major carbon sink and their removal results in a net increase in carbon dioxide
Event: South Asia has lost over 85% of its rain forests to agricultural practices. Large areas of Indonesia are losing forests at incredible rates which are beong replaces with single crops (palm oil plantation)
Cause of climate change: Trees store carbon and absorb it from the atmosphere through photosynthesis.
Through deforestation we are disallowing ecosystems to remove excess harmful carbon from its atmosphere
Intensifies the rate of climate change as increased CO2 circulates
Present impacts in natural environment: Sea level rise and Ocean acidification
Sea level rise: Global sea levels are rising at 3.6 mm annually totalling 21-24 cm since 1880, with a third of increase occurring post 2003
Rising ocean levels weaken the circulation system, which is crucial for climate regulation
Ocean acidification: ongoing decrease in the oceans pH levels
- reduces carbonate availability, weakens shells and causes coral bleaching
- Exemplified by events like the 2016 Great Barrier Reef bleaching due to 1 degree warmer temps
Projected Impacts in natural environment: Sea level rise and Ocean acidification
Sea levels forecasted to accelerate in the 21st Century, with best case scenario anticipating a rise of 0.26m to 0.5m by 2100
By centurys end, sea level rise expected in 95% of ocean areas
Acidification: projected to worsen under all scenarios with ocean pH decreasing by 0.06 to 0.07 for low emissions by 2100, threatening 90% of the world’s reefs by 2050
The East Australia current brings warm water down the east coast but it its projected that the current is strengthening and predicted Sydneys waters will be about 2 degrees warmer
Present impacts in anthropogenic environment: Urban Settlements
Many isolated cities will face urbanization challenges excacerbated by sea level rise
Cities like: Dhaka and Kolata by 2050, 68% of their global population will face urban challenges
Presently, 360 million people reside in low-lying coastal areas, with vulnerable island nations like: Carteret Islands already undergoing evacuation
Urban water scarcity, particularly in developing countries with slums, impacts around 3.6 billion people annually, worsened by shifting rainfall patterns where precipitation is prominent
Some regions will benefit from more reliable rainfall, alleviating water stress and shortages, such as Sahel region of African, which will see improved water availability in urban areas like: “Port Sudan”
Projected impacts in anthropogenic environment: Urban settlements
The IPPC forecasts that by 2050, sea level rise could displace 200 milllion people globally. Estimates suggesting 665k to 1.7 million people in the pacific alone
Maldives to face disappearance in 30-60 years due to rising sea levels which will engulf its cities
Climate refugees are expected to increase, alongside infrastructure damage, water scarcity and heightened risks from extreme weather events
Global population growing 3.6 million per week
Global Rainfall Distribution: High and Low Levels
High:
Highest concentration of rainfall occurs at low altitudes near the equator
Due to strong heating by the sun which creates a large uplift of moist air forming equatorial or heat lows which can result in thunderstorms
Mid latitudes also expereince moderate to high rainfall e.g. NZ siutated 40 degrees south of equator experiences: 1,600 mm of rainfall per year
Low:
The dry areas of the subtropics
- Desert regions of: North Africa, Central
South America. Arabian Peninsula
Inland areas with increasing distance from large bodies of water
Due to lack of evaporation and subsequent lack of moisture in the air
Because suns energy dispersed over larger area causes heat deficit
Global Temp Distribution: High and Low
High:
The hottest places on Earth are located in the Subtropical Climate Zone (25 to 40 degrees N/S of equator)
When the suns rays strike the Earth surface near the equator the incoming solar radiation is more direct
The solar radiation is concentrated over a smaller area, causing heat surplus
Areas have avg temp of 25*
Low:
At higher altitudes
The angle of incidence is smaller, causing heat energy to be spread over a larger area of the surface casuing cooler temps and heat deficit
The regions surrounding the Earth’s geographical poles recieve the least intense solar radiation as rays hit surface at an oblique angle
Rays often get refelcted, scattered, absorbed and do not emit heat
Evidence for CC over human history - Oceans
Evidence for climate change in oceans can be shown through temperature changes
Sea surface temp:
- Important indicator as more heat energy is retained in the atmosphere, the oceans absorb , more heat causing SST to increase
- This evidence for increased global temps as global SST has increased substantially during the 1990’s and have been rising by 0.33* since 1969
Ocean Acidification:
- Provides evidence for increased carbon emission in the atmosphere
- OA is the consequence of rising atmosphereic concentrations of CO2. This uptake of CO2 affects the carbonate chemistry of oceans, decreasing its pH
- Avg acidity of the worlds oceans has increased by 26% since the Industrial Revolution
Evidence over geological time - Coral
Coral reefs are extremely senistive to changes in climatic conditions, even though many reefs have existed for millions of years
These corals are affected by ocean warming which can cause them to bleach when temps rise and fall
Can also dissolve in the ocean due to increased CO2 emissions
Scientists use a hollow diamond tipped drill to gather small core samples of coral
Use x-ray imaging to observe patterns
These devices can determine past climate in tropical oceans, which help to predict future trends
Interrelationship between LCC and Climate
- Land Cover Change, as shaped by land use practices, affects the global concentration of greenhouse gases adn therefor climate
- Climate Change can affect land use and cover, creating feedback loops that can affect the climate
