1.3- Effects Of The Chaning Carbon Budget Flashcards
What is the carbon budget?
Uses data to describe the amount of carbon that is stored and transferred within the carbon cycle (similar to a household budget with some money coming in and money going out)
The impact of increasing atmospheric carbon dioxide on the land has been subject to intense research. Unfortunately, the results are unclear because the study has, so far, been over a relatively short time period. This is coupled to the fact
That there are so many other variables that could have an impact on the land and the atmosphere e.g.
- agriculture has become more intensive- more crops increases carbon dioxide take up
- increased temperatures have warmed up the land- in tundra areas, warming of the land increases the rate of decay of accumulated dead organic matter, leading to the release of carbon dioxide, methane etc
What are some impacts of the carbon cycle upon the land?
- carbon cycle is responsible for the formation and development of soil- carbon in the form of organic matter (litterfall) introduces important nutrients and provides a structure to the soil
- carbon in the form of organic matter is essential for cell growth and the production of food
- if just 10% of permafrost in the Northern Hemisphere were to thaw, it could release enough extra carbon dioxide to the atmosphere to raise temperatures an additional 0.7 degrees Celsius
Regarding the impact on the oceans, many of the observed physical and chemical change in the ocean are consistent with
Increasing atmospheric carbon dioxide and a warming climate
Because of the complex nature of the chemistry and biochemistry of the oceans and its inhabitants, many of the causative links to climate change are still not well understood. So
It is difficult to predict the precise rate, magnitude and direction of the change of carbon dioxide uptake and how that affects acidity and salinity for example (it is even more difficult to map these effects at a local scale)
What are the impacts of changing carbon budget on the oceans?
- ocean acidification
- ocean warming
- melting sea ice
- ocean salinity
- sea level rise
Explain ocean acidification
- about 30% of the carbon dioxide that has been released into the atmosphere has diffused into the ocean
- dissolving carbon dioxide in the ocean creates carbonic acid
- making slightly alkaline ocean, become a little less alkaline (more acidic)
The impact of ocean acidification on ecosystems is largely unknown, with the exception of coral reefs. It affects marine organisms in the following way:
- firstly, carbonic acid reacts with carbonate ions in the water to form bicarbonate
- however, these same carbonate ions are what organisms like coral and many plankton species need to create their calcium carbonate shells
- with less carbonate available, the animals need to expend more energy to build these shells so the shells end up thinner and more fragile
Polar and sub-polar marine systems 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
Over 10 years ago, farmed oyster larvae off the coast of Oregon in the USA began dying by the millions- why?
It was found that these losses were directly linked to 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 carbon dioxide because the more acidic water will dissolve more rock, release more carbonate ions and increase the ocean’s capacity to absorb carbon dioxide
What are the 2 main impacts of ocean warming?
- warmer oceans, a product of climate change, could decrease the abundance of phytoplankton which grow better in cool 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
BUT on the other hand, carbon dioxide is essential for plant and phytoplankton growth so an increase could increase their growth by fertilising those few species of phytoplankton and ocean plant like sea grasses that take carbon dioxide directly from the water - ocean warming also kills of the symbiotic algae which coral need in order to grow, leading to bleaching and eventual death of reefs
Explain the 2 main impacts of melting sea ice
- when sea ice melts, it is not just an indicator of a warming climate, but also part of a feedback mechanism because the highly reflective ice is replaced by 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
- sea ice also provides a unique habitat for algae, and the loss of those ice-bound algae affects marine predators all the way up the food chain from krill to polar bears
- animals like the polar bear also rely on sea ice to obtain their main food source of seals, can no longer travel upon it
Explain the impact of ocean salinity
- been an observed decrease in the deep North Atlantic, mostly likely due to higher levels of precipitation and higher temperatures
- the precipitation leads to higher river run-offs that eventually reach the sea
- these changes have been linked to a possible slowing down of the large-scale oceanic circulation in the North-East Atlantic which in turn will have an effect on the climate of North-West Europe
Although sea levels have been more or less constant for the last 5000 years, they are subject to change. Studies of coastal landforms show that they have been much _____ in the past than today
Lower
