Zusammenfassung der Ressource
Carbon Cycle and Energy Security
- How does the carbon cycle operate to maintain planetary health?
- Long-term biogeochemical cycles
- Key word:
Biogeochemical
- Key word: Carbon stores or sinks
- Photosynthesis of cyanobacteria 3 billion years ago
removed CO2 from the atmosphere and added O2 to it.
The present carbon cycle balance came about 290mya
- Key word: Movement of carbon between its
forms is the 'carbon pathway'
- Largest stores are atmosphere, hydrosphere and lithosphere
- Sedimentary carbonate rocks
- Limestone rocks formed of
calcium carbonate and marine
creatures / shells / corals
- Remains on seabed for long periods of
time --> compacted ooze and
cementation (approx. 100m under
seabed) --> deeper = fewer spaces
- Formation of crude oil
- Biological degradation --> cementation
(100m) --> diagenesis at 40 degrees --> crude
oil and natural gas (Approx. 2500m)
- Geological carbon release
- Several geological processes release
carbon into the atmosphere or into
the rock cycle over millions of years
- Tectonic forces bring carbon-rich sedimentary
rocks into contact with extreme heat which
causes chemical changes and releases CO2
- Key word: Out-gassing
- Volcanic activity releases approx. 300 million tonnes of CO2 each year
- e.g. Chemical weathering of limestone
- Short-term biological processes
- Surface and deep ocean waters
- Significant fluxes due to respiration and
photosynthesis. Phytoplankton in surface waters
use sunlight to turn carbon into organic matter and
carbon enters the food web via other organisms
that use carbon to make their shells and skeletons
- Key term: Biological carbon pump
- Starting at the surface, carbon is able to make its way
deeper in the ocean through the food chain
- Since colder water has less pressure it can hold more gas e.g.
Southern Ocean around Antarctica is a massive carbon sink
- Key word: thermohaline circulation
- Southern Ocean accounts for more than 25%
of the ocean-atmosphere exchange
- Terrestrial primary producers and soils
- Plants absorb CO2 through photosynthesis --> one of
the significant stores and fluxes of carbon
- Seasonal pattern: winter CO2 concentrations are generally higher
- Despite seasonal differences, PPM of CO2 is
increasing steadily and is currently approx. 402ppm
- Earth systems and human activities
- The NATURAL greenhouse effect
- As the Sun's energy enters the atmosphere, the
clouds reflect some of it back so that only about half
reaches the Earth's surface and lower atmosphere
- Short wavelength means the energy is able to pass in and out of the atmosphere
- Without greenhouse gases e.g. methane, water vapour we would
have an average global temperature of -6 deg Celsius
- Until approx 1750, natural geological and biological
processes controlled greenhouse gases but increasing CO2
has altered fluxes and sinks
- Oceanic and terrestrial photosynthesis
- Implications of fossil fuel consumption
- Chemistry of the atmosphere has been changed by burning of fossil
fuels with CO2 levels at their highest for possibly longer than 800,000 years
- Going to be a lag period as between 15 and 40% of CO2 remains in the atmosphere for up to 2000 years
- Possible implications for the climate, ecosystems
and hydrological cycle of a 2 degrees temp increase
- Flashcards
- What are the consequences for people and the environment of our increasing demand for energy?
- Energy security
- Consumption patterns and energy mix
- Energy mix is the proportion of each
primary energy resource in a year on a
national, global or local level
- Global energy mix largely dominated by
non-renewables namely crude oil and coal
- Switch from fossil fuels to renewable energy is being driven
by developed countries, however the change is slow
- Key term: renewable switching
- Energy pathways are
hard to break because of
geo-political links
- New
technologies
need to be
developed and
improved
- Key term: primary energy
- Key term: secondary energy
- Access to energy resources
- The energy mix of a country depends on many factors
- Real or perceived needs
of the country
- Changing consumption patterns,
perhaps linked to population growth
- Cultural and historical
legacies regarding
geopolitical links
- Accessability of primary
resources outside the country
- Availability of
primary
resources
- The financial costs of each energy option
- Benefits and problems of supplying
non-renewable energy e.g. crude oil
- PROS
- Large worldwide
demand --> $$$
- Support industry --> jobs
- Easy to transport
- More money for
public infrastructure
- Wealth
- Oil money can be invested
in new energy resources
- CONS
- Increased global warming
- Burning --> acid rain
- Oil spills e.g. Exxon Valdez
- Wars have been fought
- Dependency on oil
- Finite resource
- Middle East
- Energy players
- World Energy Council
- Energy players have three objectives: ensuring
that energy supply meets current and future
demand, ensuring accessible and affordable
energy for all and ensuring efficient use of energy
to move towards lower greenhouse gas emissions
- State-owned TNC's such as Gazprom (Russia)
or Saudi Aramco (Saudi Arabia)
- CS: State-controlled energy companies
- The Organisation
of Petroleum
Exporting
Countries (OPEC)
- Fossil fuels and economic development
- Energy pathways
- Pathways
between
consumers
and producers
may be
complex e.g.
Trans-Alaskan
pipeline across
the tundra
- Natural obstacles include vast
distances as well as difficult terrain
- CS: Trans-Alaskan pipeline
- Political tensions can also affect pathways
- E.g. Russian/ Ukraine
disputes, Somalian pirate
activity or South China Sea
- Socio-economic reasons
- Economic sanctions / embargos e.g. Russian
sanctions for invading Crimea in 2014
- Supply and demand
- Emerging economies like India
and the other BRIC's are
responsible for increased
energy consumption since 2000
- Oil was in slow decline, however,
China recently overtook the USA as
the world's largest importer
- In 2014, the EU's energy consumption
fell to its lowest level since 1985
- Unconventional fossil fuels
- Tar sands
- Where: Canada
- CS:
Canadian
tar sands
Anmerkungen:
- GOOD EXAMPLE OF HOW IT CAN BE DONE RIGHT:
- In Alberta, Canada there are 166 billion barrels of oil in tar sand reserves.
- Production increased from 0.1 million barrels a day in 1980 to 2.3 million barrels in 2014
- 151,000 jobs created
- Regulated by national bodies which set a target of 20% reduction in greenhouse emissions in Alberta by 2017
- Oil shale
- Where: Colorado, USA
- Little commercial
development anywhere
- Significant environmental
impacts e.g. releases
greenhouse gases when burnt
- Deep-water oil
- Where: Gulf of Mexico
- 63 deep-water
rigs in 2014
compared to 14
rigs in 2010
- CS: Deepwater Horizon
- Lots of new regulations are in place e.g.
robots that can heal leaks in 45 seconds
- Shale gas
- Where: USA
- Carbon footprint of shale
gas is half of that of coal
- Fracking
- Possible contamination of
groundwater and surface water
- Still a fossil fuel
- Alternative energy resources
- Renewable and recyclable energy
- IPCC said that in order to reduce
enhanced climate change,
renewable energy needs to treble
- Wind power
Anmerkungen:
- Exponential technology that has seen an incredible plunge in prices
The price of wind power has plunged since 1980 by 30 times.
Wind energy is now the cheapest power you can buy in some places around the world.
New technologies: fraction of time that wind turbines are producing energy is increasing all the time
South Africa has the world's best wind resources offshore and onshore
Offshore wind in the last four years has dropped in half in price
- Wind power as a source globally has
grown by 700% in the last decade
- Solar energy
Anmerkungen:
- In the last 40 years the price of solar power has plunged. In 1977 to buy one Watt of solar power cost about $77. Now it costs $0.30, meaning a 250 times reduction in price.
Solar power around the world has grown by 50 times in the last decade
Prices fall --> tap into new markets --> demand rises --> prices fall
Exponential growth growing at 45% per year with no sign of it slowing yet
- Solar energy is increasing very fast (38.2%
in 2014) compared to wind and HEP
- South Africa could become a solar superpower
- The growth of biofuels
- biomass is the term for substances which
have grown from animal or vegetable matter
- Europe's largest renewable energy source
- Not actually carbon-neutral due to lag period caused
by deforestation (small trees absorb less carbon)
- Biofuel is suitable for small-scale rather
than large-scale operations
- Future?
- The use of biofuels continues to grow slowly,
mainly in the USA, Mexico, Brazil and Argentina
- Seen as step
backwards
- Agave and hemp plants (super-oily)
- Radical technologies
- Hydrogen fuel cells
Anmerkungen:
- Hydrogen fuel cells
Could replace natural gas for heating or petrol for transport
Only waste product is waterIt is more efficient than petrol engine
Needs to be separated to be in its pure form and this requires a lot of energy and may emit large amounts of greenhouse gases
Not a primary energy source and hydrogen tanks need to be strong enough to withstand impacts
- Electric vehicles
Anmerkungen:
- The distances an electric car can travel without a recharge are relatively short compared with petrol cars, however this is changing.
Lack of charging points especially in the UK where 19.2% are located in London
Zero carbon emissions and nearly no noise pollution, however some people have complained that they are too quiet and pedestrians fail to hear them coming
- Carbon capture
Anmerkungen:
- Carbon capture and storage
Collects CO2 emissions from power plants and transports it to a suitable geological structure underground to make sure none of it is released into the atmosphere
- Nuclear fusion
- How are the carbon and water cycles linked to the global climate system?
- Threats to the carbon cycle and water cycle
- The growing demand for resources
- Between 1990 and 2015 the world
energy use increased by 54% whilst the
population increased 36%
- This shows that whilst population increases
energy use, it is economic development and
prosperity that account for most of the demand
- Higher population means more food production
--> deforestation --> less carbon absorption
- IPCC predicts that in 2013, 24% of
greenhouse gas emissions came from
agriculture and land-use change, such as
biomass burning, deforestation
- IPCC recommends that people switch from eating
meat to plants or other meat-substitutes and eating
generally less so that we eat no more than is required
- Ocean acidification
- As the sea absorbs more CO2 via
ocean-atmosphere exchange the pH has
decreased by 0.1pH (26% more acidic)
- Higher acidic concentrations will increase
chemical weathering at the coast especially
where there are limestone rocks
- Key term: tipping point
- Behaviour patterns of marine organisms
are expected to change -
Anmerkungen:
- Phytoplankton and microalgae might benefit from increased photosynthesis and some fish may be less sensitive
Higher acidity may affect the ability of some organisms to build shells and skeletons, creating thinner or smaller shells in molluscs and reducing the size of coral reefs
- Despite a rise in the population of
primary producers there will likely be a
decline in ecosystem productivity
- Shifting climates
- Global weather patterns may be shifting resulting in
permanent changes making the world wetter and drier
- CS: Droughts in Amazonia, South America
Anmerkungen:
- Drought usually occurs once every ten years in the Amazon
Research by UNEP showed that the trees absorb less CO2 during droughts and it was estimated that the 2005 drought emitted 5 billion tonnes of CO2
In the future, the Amazonian tropical rainforest may cease to be a carbon sink and instead become a carbon source with increasingly frequent wildfires and decomposition
- Example of positive feedback
where an increase in CO2 -->
drought --> increase in CO2
- Implications for human wellbeing
- Increased temperature and evaporation rates
- CS: Changes in the Arctic water cycle
- Largest global increase in temperature is in the Arctic
- Higher temperatures are drying up Arctic ponds
- Permafrost thawing rates will increase
- Arctic lakes will freeze later, with earlier break-up and thinner ice in winter
- Arctic Ocean could be ice-free by 2037 especially as oceans warm
and reduced sea ice will provide increased evaporation and snowfall
- Threats to ocean health
- Ocean acidification is having a massive
negative impact on marine life and as a
result for humans
- The ocean is a huge food supply
- Coral reefs becoming smaller and
bleached --> less suitable ecosystems for
marine wildlife --> less food for humans
- Bleaching is predicted to
affect half of all coral reefs
by 2050
- CS: Great Barrier Reef
Anmerkungen:
- If the CO2 levels remain at this current rate of increase, ocean acidity will increase by 150% by 2100.
Coral reefs have important environmental impacts e.g. they are a natural barrier against tropical storms and destructive waves and they protect marine life from predators whilst providing them with a nutrient-rich environment.
The Great Barrier Reef in Australia is the size of Germany and has significant economical benefits: it generates $1.5bn per annum for Australia's economy.
Coral reefs also provide humans with food and in return jobs!
- Also a loss of leisure
opportunities e.g. Great Barrier
Reef
- Forest loss
- Forest fires - 2017 Californian fires
- Respiratory issues
- 2 deaths
- 19 critically injured
- 200,000 evacuated
- Kuznets Curve
- Responses to large-scale carbon release
- Natural and human
factors and feedback
mechanisms
- In 2014, the IPCC identified 7 possible 'tipping points'
- "an abrupt, possibly
irreversible,
large-scale change
over a few decades
or less"
- Dieback of boreal forest
- Drought stress may lead to the collapse of boreal forest. Arctic
ecosystems are vulnerable to thawing permafrost, shrubs
spreading in the tundra and an increased number of pests as
temperatures rise
- Unpredictable over large area
- Arctic Ocean free of ice in the summer
- Higher air temperatures met sea ice. However, thinner
ice cover may also increase albedo and cooling
- This negative feedback is not fully understood
- Long-term droughts
- Collapse of monsoon climate circulation
- More intense precipitation occurs during the
monsoon wet season because of the transport
of more evaporated moisture in warmer air
- A sudden collapse is unpredictable
- Dieback of tropical rainforest
- Forests e.g. Amazonia could change to a less carbon-dense, drought
and fire-adapted ecosystem as a result of longer dry seasons
- Unpredictable over large area
- Seabed methane release
- Methane hydrates could be released as methane gas as a result of global warming
- Unlikely
- Atlantic thermohaline circulation collapse
- Increased volumes of freshwater could
alter thermohaline circulation
- Climate models disagree
- If emissions were stopped,
some effects of greehouse
gases would immediately be
reduced, however some would
remain for possibly centuries
- Around 20% of CO2 could
remain in the atmosphere
for hundreds of years
- Adaption strategies
- Solar-radiation management
- Flood-risk management
- Water conservation
- In China, water saving irrigation
has been introduced - between
2007 and 2009 China saved up to
11.8% of its previous consumption
- Resilient agricultural systems
- Land-use planning
- Rebalancing the carbon cycle
- CS: The Paris Agreement 2015
Anmerkungen:
- The Kyoto Protocol of 1997 set out to reduce global CO2 emissions but it wasn't a truly global agreement.
The Paris Agreement of 2015 was signed by 195 countries who all promised to reduce their greenhouse gas emissions to almost zero by 2065. The USA has since pulled out of the agreement under President Trump and this has led to many tensions, with France blocking all trade with the US until they rejoin.
However, there is little force making countries work towards their targets and progress reporting could be tampered with or plainly innaccurate.
Science suggests that the target of limiting temperature rise to 1.5 degrees above pre-industrial levels is unlikely as we have already seen a 1 degree rise in 2016.