1.3- Effects Of The Chaning Carbon Budget Flashcards Preview

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Flashcards in 1.3- Effects Of The Chaning Carbon Budget Deck (25)
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1
Q

What is the carbon budget?

A

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)

2
Q

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

A

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
3
Q

What are some impacts of the carbon cycle upon the land?

A
  • 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
4
Q

Regarding the impact on the oceans, many of the observed physical and chemical change in the ocean are consistent with

A

Increasing atmospheric carbon dioxide and a warming climate

5
Q

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

A

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)

6
Q

What are the impacts of changing carbon budget on the oceans?

A
  • ocean acidification
  • ocean warming
  • melting sea ice
  • ocean salinity
  • sea level rise
7
Q

Explain ocean acidification

A
  • 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)
8
Q

The impact of ocean acidification on ecosystems is largely unknown, with the exception of coral reefs. It affects marine organisms in the following way:

A
  • 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
9
Q

Polar and sub-polar marine systems are projected to become so low in carbonate ions within this century that waters

A

may actually become corrosive to unprotected shells and skeletons of organisms currently living there

10
Q

Over 10 years ago, farmed oyster larvae off the coast of Oregon in the USA began dying by the millions- why?

A

It was found that these losses were directly linked to ocean acidification

11
Q

A more optimistic viewpoint is that the more acidic seawater is, the better it

A

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

12
Q

What are the 2 main impacts of ocean warming?

A
  • 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
13
Q

Explain the 2 main impacts of melting sea ice

A
  • 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
14
Q

Explain the impact of ocean salinity

A
  • 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
15
Q

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

A

Lower

16
Q

Research now indicates that sea levels worldwide have been rising at a rate of ___mm since the early 1990s

A

3.5

17
Q

Causes of the rising sea levels globally since 1990s include:

A
  • melting of terrestrial ice: persistently higher temperatures have led to an increased rate of summer melting as well as a drop in snowfall in the shorter winters- this imbalance results in a significant net gain in water entering the oceans from rivers against evaporation from the oceans
  • thermal expansion: when water heats up, it expands
  • about half of past century’s rise in sea level is thought to be attributable to warmer oceans having a greater volume and so occupying more space BUT accurate measurements of this phenomenon have not yet been possible
18
Q

Although the land and the oceans will take up most of the extra carbon dioxide as much as __% can remain in the atmosphere for many thousands of years (significant because carbon dioxide is the most important gas controlling the Earth’s temperatures)

A

20

19
Q

Explain how without greenhouse gases, the Earth would be a frozen -180 degrees Celsius

A
  • carbon dioxide and methane are halocarbons are greenhouse gases that absorb a wide range of energy including infrared (heat7) energy emitted by the Earth and then re-emit it
  • the re-emitted energy travels out in all directions but some returns to Earth where it heats the surface
20
Q

Without greenhouse gases the Earth would be a frozen -180 degrees but with too many greenhouse gases, the Earth would be like Venus where the greenhouse atmosphere keeps temperatures around ___ degrees Celsius

A

400

21
Q

Clearly, the fact there is a greenhouse effect at all is good for life on Earth. The problem that is facing us is that of

A

An enhanced greenhouse effect

22
Q

The enhanced greenhouse effect is where the extra carbon dioxide and other gases in the atmosphere are causing

A

Radiative forcing

23
Q

The concept of radiative forcing is that

A
  • energy is always flowing into the atmosphere in the form of sunlight
  • some of this sunlight is reflected back to space and the rest is absorbed by the planet
  • some of this absorbed energy is radiated back into the much colder surrounding space as infrared energy
  • if the balance between the incoming and the outgoing energy is anything other than zero there has to be some warming
  • the amount that the Earth’s energy budget is out of balance is called the radiative forcing and is a measure of recent human activities
24
Q

Studies have shown that prior to 1750, radiative forcing was negligible but since then it has increased, not only because of increased greenhouse gas emissions but also

A

Changing albedos because of land use changes

25
Q

If carbon dioxide levels continue to rise at projected rates, experts predict that the Earth will become much hotter, possibly hot enough to melt much of the

A

Existing ice cover