9 - links between the water and carbon cycle ✅

Question 1

what is NOAA

Answer 1

US National Oceanic and Atmospheric Administration

Question 2

what is the evidence for climate change (2)

Answer 2

• In 2015, global mean surface temperature (GMST) was at a record +0.87 degrees C above the 1951-80 avg.
• The 10 warmest years since 1880 have all been since 1998.

Question 3

what are scientific views of climate change (2)

Answer 3

• Most climate scientists believe that global warming is caused by increasing greenhouse gas emissions. Humans are the main cause of this.
• In the 5th climate change assessment of 2013, the IPCC scientists reported they were “virtually certain” that humans are to blame for “unequivocal” global warming.

Question 4

how have CO2 levels changed over time

Answer 4

rising since 1750 from a level of 280ppm to 406ppm at the start of 2017. This is a 45% increase.

Question 5

what human activities threaten the planet (3)

Answer 5

Population growth + economic development have led to a worldwide use of carbon-rich fossil fuels as an energy source
widespread deforestation, cement flatulence
the decomposition of organic wastes in landfill sites.

Question 6

what evidence has there been at real life places (3)

Answer 6

• CO2 measurements have been taken every year at Mauna Loa since 1950 that show a 1-2ppm rise every single year.
• Cores between 3 + 4km long extracted from the Vostok ice sheet in Antarctica contain air bubbles over half a million years old.
• CO2 + methane concentrations are the highest for over 800,000 years.

Question 7

why has temperature (GMST) risen

Answer 7

Rising GMST (global mean surface temperature) is believed to be a product primarily of increases in the atmospheric carbon store

Question 8

what is the impact of rising temperatures

Answer 8

has impacted on the Earth’s energy budget:

the state of balance between incoming solar radiation received by the atmosphere + Earth and the re-radiated heat, or reflected energy.

Question 9

what is the earth’s energy budget comprised of

Answer 9

of incoming solar energy, 6% is reflected by atmosphere, 20% reflected by clouds and 4% reflected from earth’s surface

16% is absorbed by atmosphere
3% is absorbed by clouds
and 51% is absorbed by land and oceans

Question 10

explain shortwave solar radiation composition (3)

Answer 10

• Approximately 31% is reflected by clouds, aerosols + gases in the atmosphere + by the land surface.
• The remaining 69% is absorbed (50% by the Earth’s surface, especially by oceans).
• 69% of this surface absorption is re-radiated as longwave radiation.

Question 11

what is longwave radiation

Answer 11

A large proportion of the longwave radiation emitted by the surface is absorbed by the atmosphere (clouds + greenhouse gases), where it is re-radiated back to the surface + into space.

Question 12

what is the impact of longwave radiation

Answer 12

By trapping longwave radiation the “natural greenhouse effect” gives a life-supporting average 15 degrees C temp. Without it the earth would average -18 degrees C.

Question 13

what is the effect of increasing carbon emissions (2)

Answer 13

• Increasing carbon emissions (CO2 + methane) means more heat is being radiated back towards the surface, changing the energy budget.
• More heat is being retained, resulting in a warmer, more energetic climate system.

Question 14

how do greenhouse gas emissions affect the water cycle

Answer 14

There are signs the world’s water cycle + oceans have already been affected by recent increases in the atmospheric carbon store:
The cryospheric storage has shrunk dramatically.

Question 15

how has precipitation changed (3)

Answer 15

• warmth = more evaporation. Rainfall patterns change as the oceans warm up.
• UK average rainfall has not changed since the 18th Century, but in the last 30 years more winter rainfall has fallen in heavier events.
• Climate change predictions suggest UK total precipitation remains stable, but with more winter frontal rain + summer drought.

Question 16

how has high rainfall damaged the UK

Answer 16

Extreme high intensity rainfall in the UK in 2007 led to £3 billion worth of damages in floods. Higher temperatures may well mean more high intensity rainfall events.

Question 17

have extreme weather events changed (2)

Answer 17

• Some scientists believe the probability of extreme weather events has significantly increased.
• The 2012 “State of the Climate” report by the AMS showed an increasing consensus amongst leading scientists.

Question 18

what is the effect of higher precipitation on discharge

Answer 18

• IPCC climate change predictions + UK meteorologists predict more intense winter floods with increased heavy rainfall events.
• Lower river discharge levels may be seen in southern UK rivers in the summer.
• As the soil water and groundwater stores may not fully recharge, river discharge may return to normal quicker after flood events in the future.

Question 19

how have sea levels changed over time (synoptic link!)

Answer 19

• Sea levels have historically been higher in warmer periods due to thermal expansion. !Eustatic sea level rises are predicted!
• Global sea levels have risen 200mm since 1900 at about 3mm per yr.
• IPCC projections suggest a further global sea level rise of 260-820mm by the year 2100.

Question 20

what are the reasons for sea level rise

Answer 20

Glacier melt + permafrost meltwater will produce another metre of sea level rise by 2200 (even if CO2 emissions are cut dramatically).

Question 21

what would be the result of ice sheet melting in areas of the world
(synoptic)

Answer 21

The complete loss of the Greenland + Antarctic ice sheets would result in a Eustatic sea level rise of nearly 70 metres.

This will take hundreds or even thousands of years.

Question 22

how have carbon stores changes oceans

Answer 22

• Estimates suggest a third of carbon released by humans into the atmosphere has already been absorbed by oceans.
• Since 1750 the pH of the ocean’s surface has dropped by 0.1, a 30% change in acidity.

Question 23

how have oceans impacted carbon stores

Answer 23

If the oceans had not absorbed this carbon concentrations in the atmosphere would be even higher today.

Question 24

what are the effects of carbon in oceans

Answer 24

Increasing acidity could have potentially harmful effects on different marine species.

This might include impacts on metabolic rates, reproduction and immune systems.

Question 25

what has already occurred and what is projected to occur with precipitation

Answer 25

ALREADY- annual amount of precipitation unchanged, but more winter rainfall since 1980s.
PROJECTED- precipitation will become even more seasonal, but annual total will stay about the same.

Question 26

what has already occurred and what is projected to occur with UK runoff

Answer 26

ALREADY- annual runoff has increased in most parts of the UK, except the SE of England since the 1960s.
PROJECTED- uncertain due to debate about both rainfall and evaporation totals and balances.

Question 27

what has already occurred and what is projected to occur with UK runoff

Answer 27

ALREADY- increased frequency + magnitude of winter flooding since the 1980s.
PROJECTED- some studies project slightly increased flows + increased winter flooding, but not all.

Question 28

what has already occurred and what is projected to occur with evaporation

Answer 28

ALREADY- little reliable evidence to show how evaporation + transpiration have changed.
PROJECTED- potential evaporation will increase due to higher air temperatures this century.

Question 29

what are links between water and carbon cycles at the local scale

Answer 29

• Carbon is transported in solution by rivers
• Ecosystems function as stores of both water and carbon, influencing carbon transfers and water flow
• Deforestation leads to increased overland flow, causing soil erosion and the loss of carbon storage capacity
• Increasing atmospheric carbon concentrations are changing global climate and water cycle flows and stores.

Question 30

what are factors contributing to desertification

Answer 30

CLIMATE CHANGE FACTORS:
- rising carbon emissions and rising temps
- naturally occurring cyclical drought bringing lower and less reliable rainfall

LAND-USE FACTORS:
- over-grazing by cattle
- more wood biomass used for fuel and shelter by growing populations
- over-use of aquifers

PROCESS INTERACTIONS:
- vegetation loss
- reduced soil health
- overland flow and gullying
- soil removal
- NPP reduction

Question 31

how does desertification link the two cycles

Answer 31

• Reduced vegetation cover may lead to reduced carbon sequestration in biomass (due to lower photosynthesis fixation of carbon) + reduced soil carbon.
• Less vegetation cover may reduce the infiltration capacity of the remaining soil as it becomes crusted or compacted.
• Excess run-off will occur in heavy rain, resulting in soil erosion and gullying.
• Accelerated soil erosion will reduce soil carbon storage even more.
• With less soil cover, ecosystem net primary productivity (NPP) will fall further

Question 32

how can cycle linkages be explored in the UK

Answer 32

• Water and carbon cycles links can be explored at the local scale on floodplains, parks, small gardens or even patches of wasteland.
• In autumn + winter, fallen leaves can be washed by heavy rainfall into gutters and sewers. You might investigate the approximate carbon content in an area.

Question 33

how can cycle linkages be explored within rivers

Answer 33

• In drainage basins, overland flow and channel flow in the water cycle is responsible for transporting a large volume of carbon (stored as leaf litter biomass + soil organic matter) away from the land.
• At Malham Cove, limestone pavements are weathered by carbonation and solution, with the released carbon being transported away by rivers.