9 - links between the water and carbon cycle ✅ Flashcards
what is NOAA
US National Oceanic and Atmospheric Administration
what is the evidence for climate change (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.
what are scientific views of climate change (2)
- 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.
how have CO2 levels changed over time
rising since 1750 from a level of 280ppm to 406ppm at the start of 2017. This is a 45% increase.
what human activities threaten the planet (3)
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.
what evidence has there been at real life places (3)
- 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.
why has temperature (GMST) risen
Rising GMST (global mean surface temperature) is believed to be a product primarily of increases in the atmospheric carbon store
what is the impact of rising temperatures
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.
what is the earth’s energy budget comprised of
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
explain shortwave solar radiation composition (3)
- 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.
what is longwave radiation
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.
what is the impact of longwave radiation
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.
what is the effect of increasing carbon emissions (2)
- 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.
how do greenhouse gas emissions affect the water cycle
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.
how has precipitation changed (3)
- 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.
how has high rainfall damaged the UK
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.
have extreme weather events changed (2)
- 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.
what is the effect of higher precipitation on discharge
- 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.
how have sea levels changed over time (synoptic link!)
- 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.
what are the reasons for sea level rise
Glacier melt + permafrost meltwater will produce another metre of sea level rise by 2200 (even if CO2 emissions are cut dramatically).
what would be the result of ice sheet melting in areas of the world
(synoptic)
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.
how have carbon stores changes oceans
- 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.
how have oceans impacted carbon stores
If the oceans had not absorbed this carbon concentrations in the atmosphere would be even higher today.
what are the effects of carbon in oceans
Increasing acidity could have potentially harmful effects on different marine species.
This might include impacts on metabolic rates, reproduction and immune systems.
