Theme A - intro Flashcards
What does the term “sustainability” mean?
A good life for all within planetary limits.
The concept has two elements - first, a good standard of living (which might include greater resource consumption for lots of people), and secondly, environmental protection and renewable use of natural resources.
Which populations on Earth are largely responsible for unsustainable resource consumption?
Consumption worldwide is tied generally to wealth, such that wealthier urban populations generally, and especially those in countries with large economies, consume more than poorer ones. This true within nations as well as between them. 51% of the global population emit 86% of global CO2.
Why is land use a critical issue for sustainability?
Land is a precious resource and vital both for food production and climate change mitigation. This leads to conflict and competition. Agriculture is a significant emittor of greenhouse gases, while ecosystems can become absorbers of greenhouse gases in the right way. The ideal solution would be to develop strategies for using agricultural food production to sequester greenhouse gases in soils.
Can you provide some examples of co-benefits and trade-offs?
Examples might cover clean energy, where the implementation of a Green Climate Fund (SDG target 13a) could aid in progress towards ensuring universal access to affordable, reliable and modern energy services (SDG target 7.1), or food, where access to safe, nutritious and sufficient food (SDG target 2.1) could aid in reducing preventable deaths (SDG targets 3.2 and 3.4). For trade-offs, there is a tension via competition for land between climate change measures that require land (e.g. biofuel production) (SDG 13.2) and sustainable food production systems (SDG 2.4).
What are “ecosystem services”? Can you give examples of provisioning, regulating and cultural services?
Ecosystem services are the ways in which ecosystems contribute to human wellbeing. Provisioning services provide material benefits - i.e. products including food, drinking water, timber and fuel. Regulating services moderate physical and biological processes such as climate, flooding, disease incidence and water purification. Cultural services include the aesthetic, spiritual, educational and recreational benefits of ecosystems.
What proportions of land are used by people for crops, pasture and timber globally?
12% cropland, 37% pasture, 22% managed forest, 1% urban infrastructure = ~75% overall
Why is global cereal production rising faster than food calorie production?
Meat consumption is rising as part of the dietary transition, whereby diets globally are becoming more homogeneous. As well as being grazed on pasture, many livestock (especially pigs and chickens) are fed grains grown in cropland. A substantial proportion of global crop production is fed to livestock (accounting for around 40% of total crop calories). Cereals may also be used to produce biofuels.
What are the main anthropogenic sources responsible for the increases the greenhouse gasses CO2, CH4 and N2O?
CO2 sources are very clearly rooted in fossil fuel burning, with electricity and heat production being the main source, followed by transportation. Agriculture is a major source of CH4, especially the digestive systems of ruminants (cattle, sheep, goats), and rice production where soils are waterlogged. Almost as large a source of CH4, however, is fugitive (unintentional) release. Agriculture is also a major source of N2O, with the vast majority of this coming from agricultural soils.
Why are the greenhouse gasses CH4 and N2O often expressed as “CO2-equivalents”?
This ensures that their contribution to warming is expressed equally. CH4 and N2O are around 1000 times less concentrated in the atmosphere than CO2, but per tonne of gas they are much more powerful at warming. Therefore, to express CH4 and N2O as (very small) amounts of gas might give the misleading impression that they contribute very little to warming.
Describe how trend climate warming can increase extreme heat events even without any increase in climate variability. Base your explanation around the bell-shaped curve of temperature distribution.
Trend climate change shifts the whole temperature distribution bell-shaped curve into warmer temperatures. Because variability remains the same, the shape of the bell-shaped curve also remains the same. However, because the whole curve is now, on average, covering warmer temperatures, there is a higher bit of the curve over temperatures we used to think of extreme (i.e. those extreme temperatures are now much more common), and the very warmest end of the bell shape curve reaches new temperatures never experienced before (so we get heat extreme’s we’ve never experienced before).
How does warming lead to more extreme heavy rainfall events?
Warming means more evapotranspiration, so more moisture is emitted from the earth’s surface to the atmosphere. A warmer atmosphere can also hold more moisture so a larger moisture load can build up. Therefore, when it rains, the rainfall can occur in greater quantities.
Define what scientists mean by the terms “ecosystem” and “biome”.
In general, ecosystems are communities of organisms and their abiotic environment that are linked by processes of energy transfer and material cycling. By material here, we mean ‘matter’ and particularly focus on elements such as carbon, nitrogen and phosphorus, or the hydrological cycling of water. Ecosystems tend to be discussed in terms of their geographical location and the dominant organisms present, but when we are talking about an ecosystem defined by its dominant vegetation type, climate or soil conditions, scientists would typically use the term ‘biome’ instead. The biome concept is a convenient way to classify the world’s ecosystems.
Are ecosystems open or closed systems with respect to energy and materials?
They are open with respect to energy and materials, since both may be exchanged beyond the particular ecosystem that we are studying.
