Effects of changing carbon budget and impacts on atomosphere and oceans

Question 1

What are effects of changing carbon budget?

Answer 1

• 500 million years ago atmospheric CO2 was some 20 times higher than present values.
• Slow decline until industrial time
• Only way to calculate is to build computer models (between 50 and 100 interacting equations
• Result models predict possibilities, not probabilities

Question 2

What are the impacts on the land and oceans?

Answer 2

• Due to research there is not much data because it has been such a short period of time
• However current research estimates the Northern Hemisphere holds 1,672 GtC. If just 10 per cent of this permafrost were to thaw, could release enough CO2 to atmosphere to raise temperatures an additional 0.7 C by 2100
• Many observable physical and chemical changes in ocean are consistent with increasing atmospheric co2 and warming climate.
• Not understood because of many factors e.g inhabitants, difficult to map these effects at local scale

Question 3

what is ocean acidification?

Answer 3

• 30 per cent of CO2 that has been released into atmosphere has diffused into ocean through chemical exchange
• Dissolving Co2 in ocean creates carbonic acid, making slightly alkaline ocean become little less alkaline
• Impacts of ocean acidification on ecosystems is largely unknown with exception of coral reefs

Question 4

How does ocean acidification affect coral reefs?

Answer 4

Affects marine organisms in two ways:

• FIRSLTY- Carbonic acid reacts with carbonate ions in water to form bicarbonate.
• However those carbonate ions are what animals like coral and many planktonic species need to create their calcium carbonate shells with.
• With less carbonate available, animals need to expand more energy to build these shells.
• As result shells are becoming thinner and more fragile

SECONDLY- Coral reefs provide food and livelihood security for 500 million people worldwide
- Reef loss and fall in marine biodiversity threatens survival of coastal communities through food availability and reduced capacity of coastlines to buffer impact of sea level rise e.g storm surges.

Question 5

Why were oysters larvae dying in huge amounts of numbers?

Answer 5

• In 2007 on coast of Oregon and Washington in USA began dying in the million.
• Found that these loses were directly linked to ocean acidification
• From 2005 to 2009 lost production cost millions of dollars in lost sales
• Further evidence showed evidence of acidic seawater rising up from ocean depths from aproximately 30-50 years ago

Question 6

Explain land use decisions about plants that reduce CO2?

Answer 6

• More wildfires being extinguished, Leads to build up of woody material that stores carbon.
• Farmland in mid-latitudes replaced by trees which more carbon than crops
• Agriculture become more intensive, more crops from less land increase CO2 intake
• Carbon fertilisation

Question 7

Ocean warming

Answer 7

• Warmer oceans means decrease amount of Phytoplankton, which grow better in cool, nutrient rich-waters.
• Could limit oceans intake from carbon through biological pump and lessen carbon sink
• However co2 is essential for plant and phytoplankton growth, a co2 increase could increase their growth by fertilising those species of Phytoplankton and ocean plants (e.g sea-grass) that take co2 directly from water.

-Ocean warming also kill of symbiotic algae which coral needs in order to grow leading to bleaching and death of corals.

Question 8

Melting sea ice

Answer 8

• In last 35 years retreat at 40 per cent
• When ice melts not only indicator of warming but feedback mechanism because high reflective ice is replaced by more heat absorbent water.
• Sea ice also provided unique habitat for algae
• Loss of those ice-bound algae affects marine predators all the way up the food chain, from krill and fish to seals, walruses and polar bears.

Question 9

Ocean salinity

Answer 9

• Been observed decrease in salinity in deep North Atlantic.
• Caused by higher levels of precipitation and higher temperatures.
• precipitations leads to higher river run-offs that eventually reach the sea.
• Higher temperatures causing melting of Greenland ice sheet, this would lead to increase of fresh water reaching oceans
• This linked to slowing down of large scale oceanic circulation in North-East Atlantic

Question 10

Sea level rise

Answer 10

• Last glacial retreat led to a worldwide rise in sea levels about 10,000 years ago. This increase was caused by melting of land-locked freshwater ice.
• Sea levels world wide rising rate of 3.5 mm/year since 1990s
  Causes of this change:
• melting of terrestrial ice: Higher temperatures led to an increased rate of summer melting as well as drop in snowfall in shorter winters. This in-balance results in significant net gain of water entering oceans from rivers against evaporation from the ocean. Antartica and Greenland moving quickly towards oceans due to increased amount of meltwater lubricating their bases.
  Thermal expansion:
• When water gets heated it expands. About half of past century’s rise in sea level is thought to be attributable to warmer oceans having greater volumes so occupying more space.

Question 11

What is enhanced greenhouse effect?

What is Geo-Sequestration?

What is radiative forcing?

What is soil organic carbon (SOC)

Answer 11

Enhanced greenhouse effect is the impact on climate from additional heat retained due to increased amounts of CO2 and other greenhouse gases that humans have released into earths atmosphere since industrial revolution

Geo-sequestration is the technology of capturing greenhouse gas emissions from power stations and pumping them into underground reservoirs

Radiative forcing is difference between the incoming solar energy absorbed by the earth and energy radiated back to space

Soil organic carbon (SOC)- Tissues from dead plants and animals, products produced as these decompose and soil microbial biomass

Question 12

What is the concept of radiative forcing?

Answer 12

• Is that energy is constantly flowing into the atmosphere in the form of sunlight that always shines on half of the earth’s surface.
• Some of the sunlight (30 per cent) is reflected back into space and rest is absorbed by the planet. If balance between the incoming and the outgoing energy is anything other than zero there has to be some warming or cooling involved.
• the amount that the earths energy budget is out of balance is called radiative forcing