Week 6: Climate change Flashcards
Hysteris meaning
Dependence of the state of a system
Tipping point meaning
A threshold beyond which the system changes rapidly to a new state
The climate we experience is influenced by
External energy sources + internal systems variability + human forcing
Instrumental record of climate data
The direct measurement of climate variables at well-maintained stations
Climate archives
Evidence of the past recorded in geologic and biologic materials
Anthropogenic
Human produced
To investigate further back in time
We need samples of materials that formed in the past
Examples of materials that formed in the past
- Ice cores (capture annual layers of snowfall)
- Air bubbles (CO2, CH4, O2, N2O)
- H2O isotopes: temperature
- Dust, sea salt, volcanic ash
The relationship between carbon emissions and global warming
GHGs in atmosphere, basic physics + data instrumental and archives
Earth’s carbon cycle has
Fast and slow components
Fast earth carbon cycle
Biological and ocean - atmosphere exchanges
Slow earth carbon cycle
Geographical processes (making and weathering rocks)
What makes a fast transfer from rocks to atmosphere that can only be drawn back down slowly (into the ocean, then rocks)
Burning fossil carbon
Global warming impacts
- Temperature (warmer with more heat extremes, including during winter and night)
- Precipitation (changing patterns, more extreme floods and droughts)
- Sea level rise (higher coastal flooding and tides, saltwater incursion into coastal freshwater aquifers)
Ecological footprint
Measures our demands on ecosystems relative to their capacity to be restored
How many hectares are needed for restoration of our ecological footprint and how many are available
20.8 billion hectares required
12.2 billion hectares available
Global 2.6 GHA demand =
1.7 earths
NZ GHA demand =
5.4
The models used to stimulate observed change can also be used to
Project future change if we know what emissions pathway humanity will choose
Climate risk
The potential for adverse consequences for human or ecological systems, recognising the diversity of values and objectives associated with such systems.
Risks arise from
Impacts of climate change and human responses to them
IPCC
Intergovernmental Panel on Climate Change
Exposure definition
The presence of people, livelihoods, infrastructure and assets, or species and ecosystems in place and settings that could be adversely affected
Vulnerability definition
The tendency of the exposed area and its components to be adversely affected from interacting risks)
Sources of vulnerability
Demographics, geographic context, socioeconomic status, sociopolitical systems, governance and adaptation
Sensitivity definition
The degree to which a system or species is affected
Adaptive capacity
The ability of systems, institutions, people and other organisms to adjust, take advantage of opportunities, or respond to consequences
Co-benefits
Positive effects a policy or measure of one objective on others, responsive of the net effect on overall social welfare
Emission scenarios consider different future pathways including
Different social, economic, technogical, policy and governance choices
Different future pathways lead to
Different global mean warming, rates of change and impacts
Risk =
Hazard + exposure + vulnerability
3 steps to analysing risk
- Who is responsible for managing this
- Who should be consulted
- What do you think the council should do
Possible futures from the rate of risk
- Fossil fuels + cement production
- Land use, land use change
- Gross emissions = fuel combustion + cement production + land use change (deforestation)
- Net emissions = gross emissions - removals
Mitigation definition
Limiting or preventing greenhouse gas emissions and enhancing activities that remove greenhouse gases from the atmosphere
What should we be doing right now for mitigation goals
The emergency response requires quick wins: actions we can take now that yield immediate decarbonization without requiring new infrastructure
Quick wins in the built environment involve
- Lower cost
- Existing technology
- More solar and wind
- Efficiency and optimisation
- Weatherization, insulation, building automation
- Fuel efficient vehicles and alternative transportation
- Sustainable diets and reduce food waste
- Stop deforestation and start restoration/reforestation
To keep a low carbon future, we need
New infrastructure, to support existing and new low carbon technology
New infrastructure in a low carbon surface involves
- New planning required, complex, replacement
- May be new or higher cost
- Industrial fuel switching
- Electrification from renewable sources
- More distributed electricity generation
- Update buildings for efficient electrification
- Terminal and tracks mass transit: busses and trains
- Charging infrastructure
- New farming practices (reducing carbon, CH4, N2O etc)
- Waste sorting and recovery
Some activities require new technology because they are hard to
Decarbonise (manufacturing cement and steel, jet fuel)
Industrial and chemical processes may be a possible way to draw down
CO2 (however research suggests they emit more than they bring down)
The only assured way to achieve draw down goals
Storage approaches
