climate change 2 Flashcards
climate change, greenhouse gases and climate scenarios (18 cards)
weather definition
current atmospheric conditions
climate definition
general weather conditions over a long period of time
Early evidence of climate change
- first proposed by C.S. Callendar in 1938
- associated that to industrialisation and CO2 release
- only in mid to late 20th century when most data supporting climate change was first seen
- shows global worming through global weather stations (e.g. NOAA)
- trend of increased global average surface temperature
- 2024 is the warmest year on record
Greenhouse gas effect
Natural process where gases trap radiation from sun warming earth
- now experiencing enhanced greenhouse effect
Intergovernmental Panel on Climate Change (IPCC)
- international body for the assessment of climate change
- established by UN environmental programme and the world meteorological organisation (WMO) in 1988
- aim: to provide clear scientific view on the current state on knowledge in climate change and its impacts
- the reports have shown a continued elevation of temperature even when measure over a long time period
- IPCC statement says human influence on climate system is clear and warming of the climate system us unequivocal.
- NOAA confirmed 20 major climate-related disaster events.
- weather is more extreme and more unpredictable. Already impacting financially, socially etc
Greenhouse gas effect
- natural process is important so earth is not too cold to support life
- without GHG earths average temperature would be -18 degrees Celsius but instead it is +15 degrees
- GHGS include water vapour, carbon dioxide, Nitrous oxide, ozone and methane
- some GHGs have a greater effect on the warming effect than others e.g. methane is 80x more effective than CO2.
- this is caused by anthropogenic processes
Seasonal peak in CO2 emissions due to fuel usage in the winter being higher
Methane (CH4)
Methane is more than 28 times as potent as carbon dioxide at trapping heat in the atmosphere
released by ruminants (cows and sheep) as a bioproduct of the gut process
rice paddy
Nitrous oxide (N2O)
volatilisation of nitrogen (nitrification and denitrification) release N2O as side product, mainly from fertiliser applications
Representative concentration pathways (RCP)
- these model for different scenarios
- we are currently on track to RCP 8.5
- this was produced by IPCC in 2014
mitigation and adaptation to climate change
Mitigation: emission reduction (Paris agreement, Kyoto protocol)
Adaptation: deal with changes in climate
ecosystems
organisms with their abiotic environment identifiable area/space
producers (green plants, algae etc photosynthetic): autotrophs
consumers (herbivores, carnivores, parasites etc)
decomposers (soil fauna, fungi, bacteria): heterotroph
Photosynthesis
- also carbon fixation, assimilation
- all our food and most of our energy consumption goes back to photosynthesis
- fossil fuels and fossil products of past photosynthesis
Respiration
- degrades energy rich compounds
- consumes O2 produces CO2
- running day and night
- most organisms respire
Flow of energy and matter in an ecosystem
- ecosystems can function without the consumers
- driving energy source is sun
- ecosystems are thermodynamically OPEN systems so can exchange energy and matter with the outside
Ecosystem productivity
Measured in g biomass per year and ha; or g C year-1 m-2
Gross Primary Productivity (GPP) = C fixed in plant photosynthesis
Net Primary Productivity (NPP) = GPP – plant respiration
Net Ecosystem Productivity = NPP – heterotroph respiration
(animals, decomposers)
NPP varies greatly globally
The carbon fertilisation effect
- photosynthesis has benefited from higher CO2
- the earth has larger leaf area than before climate change
- proves that sequestration of carbon from plants can help manage increasing CO2 and therefore the benefit of planting schemes
Climate change and European agriculture
- goal is to reach net zero emissions
- total GHG emissions from agricultural sector
- agricultural emissions driven by meat and dairy production (cows)
- way that soils are fertilised is the second largest driver of agricultural emissions
road to net zero
mitigation: carbon accountability; land use change
potential for new production systems
adaptation: barriers, adoption, integration, improved genetics
development and implementation of new crop varieties
