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Question 1

enhanced greenhouse effect

Answer 1

31% of short wave radiation is reflected by clouds, aerosols and gases in the atmosphere and by the land surface.​

The remaining 69% is absorbed, particularly by the oceans. ​

When long wave radiation is reflected back, a large amount is re-radiated back to Earth by clouds and GHGs which traps the long wave radiation in our atmosphere. ​

The natural greenhouse effect and gives us our life supporting average temperature of 15 degrees. Without this effect our average temperature would be -6. ​

Question 2

Holocene or Anthropocene?​

Answer 2

The present geological time we are living in is called the Holocene period but many people refer to it now as the Anthropocene because of the profound changes caused by humans. ​

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The natural greenhouse effect has become enhanced; C02 in the atmosphere has increased in volume by 40% in the last 300 years.

Question 3

Causes of GHGs

Answer 3

Industry​
Combustion of fossil fuels​

Agriculture​:
Livestock – methane​
Deforestation – farm land​
Loss of soil carbon from ploughing​

Transport ​
CO2 emissions

Electricity generation​
Increased demand due to rising population

Cement Production​

Wetland/peatland loss​

Question 4

Cement Production

Answer 4

The most consumed product in the world after water.​

Chemical processes involved in production release a substantial amount of carbon dioxide (6% of global carbon emissions).

Question 5

Wetland/peatland loss

Answer 5

The nature of wetlands is shaped by water and rainfall patterns – the unpredictable change due to climate change may result in wetlands drying out.​

Peatlands store 550Gt of carbon – twice as much as all of the world’s forest biomass combined but only cover 3% of the earth’s surface.

Question 6

Human Activity

Answer 6

Through burning fossil fuels we have transferred considerable amounts of carbon from fossil stores, where exchanges are very slow, into the fast category, significantly disturbing the carbon cycle.​

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CO2 levels in the atmosphere are higher than ever before.​

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This process has continued since the Industrial Revolution (1760-1840) and accelerated through the oil age (20th century), changing the chemistry of the atmosphere.

Question 7

Climate Patterns – temperature and precipitation

Answer 7

Carbon dioxide and other GHGs naturally help to maintain the Earth’s temperature – and also determines the distribution of temperature and precipitation.​

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If the concentrations of these change, it is likely to alter these distribution patterns.

Question 8

Temperature

Answer 8

The amount of solar energy (solar insolation) reaching the Earth’s surface varies at different locations which in turn influences temperature.​

The angle of the sun’s rays makes solar insolation intense at the equator but dispersed over a wider area at the poles. ​

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Different characteristics of the Earth’s surface (how light or dark it is) also affects how much heat is absorbed or reflected.

Question 9

Precipitation

Answer 9

The heating of the atmosphere and surface controls the temperature, pressure, movement and moisture content of the air.​

Because solar radiation is most intense at the equator, low pressure systems dominate there, meaning rainfall all year round.​

Regional and seasonal variations also ​

occur, because of the effects of relief, pressure patterns and wind systems.

Question 10

Evidence of change​

Answer 10

The IPCC (Intergovernmental Panel for Climate Change) has been collecting evidence of natural changes of heat sources such as volcanism, solar changes and orbital changes such as the Milankovitch cycle and none of these can account for recent changes. ​

Question 11

Fossil fuel consumption – what’s the problem?​

Answer 11

Levels of CO2 in the atmosphere are now higher than ever before (compared with air bubbles found in ice cores up to 800,000 years ago).​

Fossil fuels continue to be the primary energy source for driving modern civilisation.​

Fossil fuels combustion creates fast carbon cycling.​

Without it, the carbon in the fossil fuels would transfer slowly through volcanic activity.​

The IPCC estimated that between 1750 and 2011 the concentration of CO2 in the atmosphere increased by 40%.​

With approximately 50% of those emissions still in our atmosphere today. ​

Carbon remains in the atmosphere for about 2000 years so climate change will continue for some time yet.​

Question 12

Impacts of using Fossil Fuels​

Answer 12

The combustion of fossil fuels is explicitly linked greenhouse gas concentrations, rising global temperatures and sea levels.​

There are three main areas of impact you need to be aware of…​

Climate​EcosystemsHydrological Cycle

Question 13

Key concept: Climate forcing

Answer 13

• The impacts of fossil fuel combustion on climate are at global and regional scales.
• The 2014 IPCC report, aimed at policy makers, explicitly linked greenhouse gas concentrations to fossil fuel emissions, rising global temperatures and sea levels
• Global warming and the alteration of ocean temperatures and salinity levels could affect the thermohaline current by slowing or reversing the North Atlantic Drift (NAD), also called the Gulf Stream.
• This happened 20,000 years ago when temperatures dropped.
• The NAD keeps UK temperatures 5°C higher than they would otherwise be in winter.

Question 14

Climate predictions
Global

Answer 14

On average, the Earth will become warmer, hence more evaporation and precipitation
Sudden shifts in weather patterns
More extreme, intense and frequent events: floods, droughts
Rising mean sea level

Question 15

Climate predictions
Regional

Answer 15

Some regions will become warmer and drier, others wetter
Some regions will have less snow, more rain
Storm surges may increase

Question 16

: Positive feedback

Answer 16

• Global warming creates ice melt, and permafrost thawing releases trapped methane.
• Drying forests and warming oceans emit CO2.
• Increased greenhouse gases mean increased warming.

Question 17

Implications for ecosystems

Answer 17

• Ecosystems are valued for the services they provide for the planet as well as for humans, helping regulate carbon and hydrological cycles.
• By the end of the century, global warming and its impacts may be the dominant direct driver of changes in these services and in biodiversity.
• Already at risk are species with low population numbers, limited climatic ranges and restricted or patchy habitats.
• There is increasing evidence of changes in the distribution and geographical
  ranges of species, their population size and timings of reproduction and migration.
• Marine organisms are threatened with progressively lower oxygen levels and high rates and magnitudes of ocean acidification, as well as rising temperatures, which may alter the foundation of the food chain: plankton growth.
• Impacts on coastal ecosystems and low-lying areas at risk from sea level rise will continue for centuries, even if the global mean temperature stabilises.
• Although more species will be negatively affected by climate change, there may be some that benefit.
• Cool, moist regions such as the UK could provide habitats for additional species, while in hotter, arid regions species diversity may decline.
• The two biomes most at risk immediately are Arctic and coral ecosystems

Question 18

Implications for the hydrological cycle

Answer 18

• increase evaporation rates and hence trigger more moisture circulating throughout the cycle, rather than storage in oceans, and intense precipitation events
• change precipitation type, as in the northern hemisphere where spring snow cover has decreased in extent; earlier springs mean earlier peaks in snowmelt and resulting river flows and flows into oceanic stores
  increase surface permafrost temperatures, a trend recorded since the early 1980s
  reduce sea ice, ice cap and glacier storage, as in the Arctic already
• change the capacity of terrestrial ecosystems to sequester carbon and store water; an example of the importance of water storage is in the Amazon, where 60 per cent of precipitation originates from evapotranspiration by upwind ecosystems.
• Lastly, the complex El Niño-Southern Oscillation (ENSO) is an important factor in the Earth’s climate system and affects the hydrological cycle. Droughts and floods driven by ENSO may be more intense and increase in frequency because of a warming atmosphere and ocean surface.