Carbon Facts

…% carbon in forests is stored in biomass, …% in soil

30%

70%

what percentage of carbon is stored in biomass and soil in tropical rainforests?

50-50

what were the preindustrial carbon dioxide levels in the atmosphere

270 ppm

what is the concentration of carbon dioxide in the atmosphere right now?

420ppm

list the stores of carbon, in order of how much they store

sedimentary rocks > ocean deep layer > fossil fuels > soil > ocean surface > atmosphere > terrestrial biomass

…% of anthropogenic emissions are from hydrocarbon extraction + burning and cement manufacture

87%

global cement manufacture contribues ..% to global CO2 emissions

5%

since which year has there been energy insecurity?

2004

also a global energy crisis began in the aftermath of the COVID-19 pandemic in 2021, with much of the globe facing shortages and increased prices in oil, gas and electricity markets

how much forest is deforested each year?

an area the size of Greece

…% of anthropogenic emissions are from land use change (mainly deforestation)

30

what proportion of the world’s population live in urban areas?

Over half of the world's population lives in urban areas, reflecting a significant global trend towards urbanization. 60% by 2030

what is the largest source of CO2 in the atmosphere?

ocean outgassing

how has the pH of the oceans changed since 1750

The pH of the oceans has decreased by about 0.1 units since 1750, indicating increased acidity due to higher CO2 absorption.

what would happen if just 10% of permafrost in the northern hemisphere thawed?

would release enough CO2 to increase global temperatures by 0.7 degrees by 2100

importance of coral reefs

Coral reefs provide essential habitats for marine life, protect coastlines from erosion, and play a crucial role in carbon cycling.

provide food and livelihood security for 500mn people worldwide

how much has arctic sea ice retreated in the last 35 years?

40%

how much of global land is covered by peat?

4mn km²

in 2016, bleaching of the Great Barrier Reef killed …% of reef’s coral

40%

how much CO2 must be removed from the atmosphere each year to make a difference?

10bn tonnes

it is predicted that by 2050, global aviation emissions of CO2 will be …% more than in 2005

300-700%

global renewable energy generation is forecast to climb …% from 2023

90%

define net primary productivity

Net primary production (NPP) refers to the amount of energy available to herbivores in the plant's biomass after plant respiratory loss. It is the rate at which an ecosystem accumulates energy or biomass, excluding the energy it uses for the process of respiration.

what factors affect NPP?

Factors affecting net primary productivity include sunlight, nutrient availability, water supply, temperature, and the types of plants present in an ecosystem.

peat

Peat is formed when organic matter accumulates faster than it decomposes due to the lack of oxygen in waterlogged conditions. Peatlands are the most carbon dense of any terrestrial ecosystem in the world

advantages of carbon sequestration

• Can be fitted to existing coal power stations

• Captures 90% of CO2 produced

• There is a demand for CO2 (Coca Cola, Plant growth, beer etc), so transport systems via pipeline in liquid form already exist

• Potential to capture half the world’s Co2 emissions

disadvantages of carbon sequestration

• High cost is the main restriction to the growth of CCS

• Increased energy demand of power stations

• May not be space to fit it to existing power stations

• Economically viable in some cases as it is used to push oil out the ground, thus further increasing fossil fuel usage

geologic sequestration

CO2 is captured at its source (for example, power plants or industrial processes) and then injected in liquid form into stores underground. These could be depleted oil and gas reservoirs, thin, uneconomic coal seams, deep salt formations and the deep ocean.

oceanic sequestration

The process of capturing CO2 from the atmosphere or point sources and storing it in the ocean, where it may help reduce atmospheric carbon levels. By the time this carbon reaches the seabed it has entered the Earth’s geological cycle.

terrestrial/biologic sequestration

this involves the use of plants to capture CO2 from the atmosphere and then to store it as carbon in the stems and roots of the plants as well as in the soil.

disadvantages of terrestrial sequestration

• a forest planted to capture carbon might lose that carbon back to the air in a catastrophic forest fire or if the forest suffers disease or infestation.

• Land-based sequestration plantations are slow growing and require active monitoring and management for the lifetime of the plantation, usually many decades.

• The carbon within those systems is never removed permanently from the atmospheric system.

vertical deep mixing / oceanic carbon pump

• occurs when warm water in oceanic surface currents is carried from the warm tropics to the cold polar regions.

• Here the water is cooled, making it dense enough to sink below the surface layer, sometimes all the way to the ocean bed.

• When cold water returns to the surface and warms up again, it loses CO2 to the atmosphere.

• In this fashion, vertical circulation ensures that CO2 is constantly being exchanged between the ocean and the atmosphere. This vertical circulation also acts as an enormous carbon pump, giving the ocean a lot more carbon than it would have if this surface water was not being constantly replenished.

biological pump (in oceans)

• Carbon gets incorporated into marine organisms as organic matter or structural calcium carbonate.

• When organisms die, their dead cells, shells and other parts sink into deep water.

• Decay releases carbon dioxide into this deep water.

• Some material sinks right to the bottom, where it forms layers of carbon-rich sediments.

• Over millions of years, chemical and physical processes may turn these sediments into rocks. This part of the carbon cycle can lock up carbon for millions of years.

  
  

precession

the gradual change in the direction of Earth's axis of rotation. It's similar to the way a spinning top wobbles. The greater the precession (wobble) and axial tilt the greater the climatic extreme of hot or cold

eccentricity

a measure of how elliptical the Earth's orbit is, or how far it deviates from a perfect circle. If the Earth’s orbit is more circular then the seasonal difference is not as great and this results in a cooler planet. Elliptical orbit of the Earth creates more seasonal variations and this leads to climatic extremes of warming or cooling

axial tilt

the gradual change in the angle between Earth's rotational axis and its orbital plane

how do asteroid impacts affect the carbon cycle?

Asteroid impacts can significantly contribute to climate change by ejecting large amounts of dust and aerosols into the atmosphere, which block sunlight and cause global cooling in the short term; however, depending on the composition of the asteroid, the long-term effect could be warming due to the release of greenhouse gases like carbon dioxide from vaporized rock upon impact.

why have we been in a state of energy insecurity since 2004?

• geopolitical tensions (Russian invasion of the Ukraine and Economic sanctions vs energy dependency e.g. 60% of Germany’s natural gas comes from Russia)

• fluctuating oil prices (e.g. due to terrorist activity in Nigeria and Iran)

• increased demand for energy (e.g. China, Brazil)

• finite fossil fuel resources

• the insufficient transition to renewable energy sources.

pros and cons of using oil over coal

Pros: Oil generally produces 20% less carbon dioxide and pollutants than coal when burned, making it cleaner in terms of air quality

Cons: coal is typically more abundant and cheaper, which can lead to more economic benefits in energy production. Oil extraction can be environmentally damaging in other ways such as oil spills (Deepwater Horizon accident in 2010) and Tar Sands extraction (Alberta, Canada)

CO2 emissions due to farming practices

• When soil is ploughed the soil is aerated and microbial activity dramatically increases - this breaks down humus into nutrients and produces CO2 more rapidly

• The single largest source is enteric fermentation - livestock producing methane (CH4) during digestion. In 2011 this was 39% of the agricultural sectors GHG outputs

• Rice paddies create CH4 during anaerobic decomposition 10% of total agricultural emissions

• Burning topical grasslands 5%

In 2012, cities were responsible for ..% of global carbon emissions. Under a business-as-usual scenario, this share of emissions is predicted to increase to ..% by 2030.

47%

49%

what is the carbon budget?

• The carbon budget is the amount of carbon stored and transferred within the carbon cycle on global or local scale

• The budget includes carbon emissions by various processes (i.e. burning fossil fuels) against natural or human sequestration

•  Calculated using a carbon footprint calculator and is defined as:

the total amount of greenhouse gases produced (directly and indirectly) to support human activities, and expressed in gigatonnes of carbon dioxide equivalent per year (GtC/yr)

natural sources of carbon

• respiration

• decomposition

• ocean outgassing (greatest emitter)

• volcanic eruptions

natural greenhouse effect

• Short wavelength UV radiation reaches the Earth - radiation absorbed, and then re-radiated as longer wavelength infrared radiation

• Longer wavelength IR radiation is absorbed by the greenhouse gases and re-radiated again and is absorbed again by the earth and repeats - this heat is trapped within the atmosphere which facilitates life on earth - this is the natural greenhouse effect

enhanced greenhouse effect

The enhanced greenhouse effect / anthropogenic climate change / climate change / global warming is caused by the addition of greenhouse gases into the atmosphere which further increases the temperature of the planet/atmosphere

solubility cycle

colder sea water will dissolve more atmospheric CO2. about 30% of atmospheric CO2 has been diffused into the ocean to form carbonic acid. The ocean is naturally alkaline but since 1750 the pH has dropped by 0.1 - a process known as ocean acidification

biological cycle (oceans)

• microscopic organisms known as phytoplankton photosynthesise and absorb CO2 from the sea.

• These plankton are consumed by zooplankton who release the carbon as faecal matter where it sinks to the ocean floor and contributes to the carbon rich marine deposits.

• eventually form carbonate rich sedimentary rocks

impact of carbon cycle on the earth

• Releases CO₂ and other greenhouse gases that absorb outgoing long-wave radiation; warming the lower atmosphere

• Ash and gases from volcanic activity release CO₂, which again absorb insolation, cooling the earth

• Phytoplankton can release dimethyl sulphide into the atmosphere, which can increase cloud formation (water vapour)

• Plants remove CO₂ and release water and oxygen; areas of dense vegetation shows increased precipitation rates

impacts of the carbon cycle on the atmosphere

• CO2 in the atmosphere warms the Earth through the natural greenhouse effect

• Increases in carbon emissions has led to the enhanced greenhouse effect and threatens the delicate atmospheric balance

• Carbon is stored by vegetation and act as carbon sinks, holding carbon on a short-term basis. Wildfires and deliberate burning, releases carbon quickly into the atmosphere

• Deforestation disturbs the balance between length and capability of trees to store carbon, removal of trees not only releases carbon, but also reduces the availability of oxygen and water

impacts of the carbon cycle on the land

• Soil is made from organic matter and cycled through the carbon system, which also brings important trace nutrients to assist in further vegetation growth

• Carbon stored in grass provides food for animals - hay, silage etc. 

• Carbon also provides energy in the form of fossil fuels (hydrocarbons) and wood

• Carbon also provides a valuable resource in charcoal, diamonds and graphite

impact of the carbon cycle on the ocean

• Calcium carbonate is derived from carbon and is utilised by marine animals to build shells and skeletons

• Plant and animal remains are dropped to the ocean floor and compress into sedimentary rock and hydrocarbons effectively locking carbon in a long-term cycle

• Phytoplankton utilise CO2 during photosynthesis, which is then transferred along the marine food chain

• Increased levels of CO2 and warming of the oceans has led to algal blooms and blocking of sunlight for photosynthesis by phytoplankton 

ocean changes

• Ocean warming - effects on phytoplankton and thermal expansion

• Melting sea ice

• Ocean salinity

• Ocean acidification

causes ocean acidification

• About 30% of the CO2 that has been released into the atmosphere has diffused into the ocean through direct chemical exchange.

• Dissolving carbon dioxide in the ocean creates carbonic acid.

• This makes the slightly alkaline ocean become a little less alkaline.

• Since 1750, the pH of the ocean surface has dropped by 0.1, a 30% change in acidity

impacts of ocean acidification

• shells end up being thinner and more fragile - this is because carbonate ions react with carbonic acid to create bicarbonate, meaning less carbonate available for shell creation

• Coral reefs provide food and livelihood security for 500mn people worldwide. Significant reef loss and the consequent fall in marine biodiversity threatens the survival of coastal communities through reduced food availability and a reduced capacity of coastlines to buffer the impact of sea level rise, including increased storm surges

• Polar and sub-polar marine ecosystems are projected to become so low in carbonate ions within this century that waters may actually become corrosive to unprotected shells and skeletons of organisms currently living there.

example of an impact of ocean acidification

in 2007, farmed oyster larvae off the coast of Oregon and Washington in the USA began dying by the millions. It was found that these losses were directly linked to ocean acidification - costs millions of dollars in sales

good thing about ocean acidification

A more optimistic viewpoint is that the more acidic seawater is, the better it dissolves calcium carbonate rocks (chalk and limestone). Over time this reaction will allow the ocean to soak up excess CO2 because the more acidic water will dissolve more rock, release more carbonate ions and increase the ocean’s capacity to absorb CO2.

cons of ocean warming

• Warmer oceans, a product of climate change, could decrease the abundance of phytoplankton, which grow better in cool, nutrient-rich waters. This could limit the ocean’s ability to take carbon from the atmosphere through the biological carbon pump and lessen the effectiveness of the oceans as a carbon sink.

• Ocean warming also kills off the symbiotic algae which coral needs in order to grow, leading to bleaching and eventual death of reefs

pros of ocean warming

On the other hand, CO2 is essential for plant and phytoplankton growth. An increase in CO2 could increase their growth by fertilising those few species of phytoplankton and ocean plants (like sea grasses) that take carbon directly from the water

melting sea ice

Arctic sea ice has retreated 40% in the last 35 years. When sea ice melts, it's not just an indicator of a warming climate but also part of a feedback mechanism because the highly reflective ice is replaced by a more heat absorbent water. When it starts to melt the ocean is able to absorb more sunlight, which in turn amplifies the warming that caused it to melt in the first place.

ocean salinity

There has been an observed decrease in salinity in the deep North Atlantic. This is probably caused by higher levels of precipitation and higher temperatures. The precipitation leads to higher river run-offs that eventually reach the sea. The higher temperatures are causing melting of the Greenland ice sheet and many alpine glaciers. This too will lead to an increase in fresh water reaching the oceans. These changes have been linked to a possible slowing down of the large-scale oceanic circulation in the North-East Atlantic. This in turn will have an effect on the climate of North West Europe.

radiative forcing

a measure of how the energy balance of the Earth"s atmosphere is altered by greenhouse gases, aerosols, and land use changes. It quantifies the influence of these factors on climate change.

carbon fertilisation

the enhancement of plant growth due to increased levels of carbon dioxide in the atmosphere, which can lead to greater biomass and crop yields.

..% of the carbon in the earth’s biosphere is stored in plants

19