W + C: The Carbon Budget

Question 1

What is the carbon budget?

Answer 1

the Carbon Budget use data to describe the amount of carbon that is stored and transferred within the carbon cycle.
- Carbon is measured in units of mass called pentagrams (pg) 1pg = 1 gigaton
- essential for understanding how carbon emissions contribute to the changes in the Earths Environment.

Question 2

Why is the global carbon budget changing?

Answer 2

because fossil fuel emissions are increasing and ocean carbon sink uptake is decreasing so overall there is more carbon in the atmosphere due to climate change.

Question 3

What’s some general facts about the carbon budget?

Answer 3

• land use emissions are increasing but fluctuating by +/- 0.7.
• Fossil fuels and land use emissions are the main factors to changing CB. an extra 5.4 gigatons of carbon emissions are entering the atmosphere each year.
• CB allows scientists to roughly calculate how much CO2 can add to the atmosphere before worst climate change effects.
• latest budget estimate; limit of 3.2 trillion metric tones of CO2 gives the world a 66% chance of avoiding runaway global warming. Nearly 2/3 of CB has been spent though.
• if CO2 emissions remain at 2022 levels, CB will be exhausted by 2029, so warming of 1.5 DC above pre-industrial levels.

Question 4

What are some of the general impacts of the carbon budget?

Answer 4

• most important role of carbon cycle is release of CO2/methane. These absorb long-wave radiation and warm earth, for life to exist.
• But - increased emissions from anthropogenic have increased concentration of greenhouse gases making them more effective in trapping radiation = enhanced greenhouse effect.
• explains increased global temps of 0.8 DC since 1880.

Question 5

What are some of the impact of changing the carbon cycle on land?

Answer 5

• thawing permafro -> lead to positive feedback - releasing more carbon/methane as organic material thats been stored long periods rots…
• More CO2 —> more photosynthesis and plant growth (‘carbon fertilisation’) limits are reached when nutrients/water limits are reached.
• more wildfires as temps increase.
• changes where types of farming carried out.
• Warmer temps lead to longer growing seasons - more plant growth and higher evapotranspiration rates require more water. Growth is limited by water availability.
• desertification may occur in some areas
• Flooding may occur, creating wetland habitats.
• CO2 taken by plants increased since 1960, 25% of emissions removed by plants.
• Agriculture is more intensive, more crops form less land increase CO2 take up.
• Increased temps warmed up land, in Tundra areas, this increases rate of decay of accumulated dead organic matter leading to the release of CO2, methane, etc.

Question 6

What is the impact of changing Carbon Budgets for oceans?

Answer 6

• 30% of the CO2 released has diffused into the sea (creating carbonic acid)
• Ocean acidification makes oceans less alkaline. Carbonic acid reacts with carbonate ions to form bicarbonate. Less carbonate ions are available, so corals and planktonic species shells will become thinner and more fragile.
• Coral reefs provide food and livelihood for 500 million people worldwide. Reef loss and fall in diversity threaten coastal communities
• Effect on oyster farming - highly negative to communities in Oregon and Washington, which rely on oyster fishing
• Ocean warming - decreases the amount of phytoplankton - could limit the oceans ability to take carbon from the atmosphere and lessen the oceans effectiveness as a carbon sink. Carbon is essential for phytoplankton growth and ocean plant growth.
• Sea level rising at rate of 3.5mm/year - a result of melting terrestrial ice and thermal expansion. If continues to warm, oceans are expected to rise between 0.8 and 2m by 2100.
• ocean warming kills off symbiotic algae which corals need to grow - leading to bleaching and eventual death of coral. Warmer water is less able to absorb CO2.
• Melting sea ice - positive feedback loop, effects life from krill to seals, walruses and polar bears.
• decreasing salinity in North Atlantic due to higher levels of precip and higher temps. Melting ice also leads to more fresh water reaching the oceans - effect movement of ocean currents - possibly slowing down North East Atlantic oceanic circulation.

Question 7

What’s the impact of changing the carbon budget in the atmosphere?

Answer 7

• 20% extra carbon could endup in atmosphere. - GH effect - gases absorb infrared energy emitted by the Earth, then reemit it.
• Radiative forcing is how out of balance the gap of incoming and outgoing energy is.
  —> currently it is 1.6 watts/m2 - not good.
• more severe storms also a consequence.

Question 8

What is the impact of changing carbon budgets on the climate?

Answer 8

• Vegetation removes CO2 and releases water and oxygen. Regions with dense vegetation have high rates of photosynthesis and respiration - increases humidity levels, cloud cover, and affects regional temps and rainfall
• Widespread deforestation cause drier areas and less humidity. less photosynthesis.
• proliferation of plankton in ocean promotes cloud formation through creation of substance dimethyl sulphide. Yet, plankton are in decline.
• Volcanic eruptions release CO2, along with ash and sulphur dioxide. The sulphur dioxide absorbs more incoming radiation from sun and may lead to cooling affect —> volcanic winter.