lecture 23- climate change model scenarios Flashcards
What are the ranges of responses to environmental problems?
1- Doing nothing
2- Mitigation, or the action of reducing the severity or seriousness of a (environmental) problem.
3- Adaptation, or reducing our vulnerability to impacts by increasing our resilience or capacity to deal with them.
What are the consequences of the range of responses?
Adaptation, mitigation, and doing nothing are not mutually exclusive.
And each choice comes with consequences (refer to triangle in notes).
What is the challenge of scenarios?
Near an infinite number of possibilities; no way to know which is correct, and which could be reasonable.
Are scenarios predictions?
No. Scenarios allow investigations of the implications of various developments and actions (“what-if”),
What is the issue with scenarios that is specific to climate modeling?
Given the complicated nature of Earth system models, only a few scenarios can be properly evaluated, and every group must use similar scenarios to permit comparisons.
We must arbitrarily choose a few scenarios that simultaneously capture the range of possible futures while being meaningful and useful for planning.
How Do We Come Up With Scenarios?
A consensus must be established on a limited set of different enough scenarios to learn from those differences and estimate associated uncertainties; Requires lots of coordination, we need institutions to help us.
For coordinated efforts at an international level, this is generally taken care of by a dedicated organization: IPCC
What are the drivers of IPCC scenario-making?
1- Geophysical driving forces: GHG and aerosol emissions, land use, Earth system response;
- emissions will shape what will happen-what worsens climate change or things that help
2- Socio-economic driving forces: Population, technology, economic development, and associated energy needs and geophysical implications (emissions, land use, etc.);
What drives how we approach the problem?
1- Societal/policy drivers: emphasis on sustainability, regional rivalry, inequality, fossil fuel-intensive development…
2- Types of possible responses (e.g., mitigation, adaptation),
agreed-upon targets (e.g., “well below 2°C”)
- or you can temporarily forget about the future, and focus on a goal- collectively decide on a degree limit, but if we pass it what are the implications.
Explain the institutional IPCC context.
Need for a range of outcomes to grasp the many issues;
Working groups coordination: scientific basis, impacts, response.
What are the dominant IPCC Scenarios?
1) Create categories of scenarios (“socio-economic pathways”) rooted in challenges of different types of responses.
2) Complement with an associated radiative forcing by 2100.
What does it mean for the IPCC to be milestone-centric? Why do they do this?
For example, what will climate change look like when a particular threshold is reached, such as 2°C warming.
Likely reason: patterns look similar for all scenarios at a specific threshold; what changes for a given scenario is if or when that threshold is reached.
What are the predicted temperature changes?
- More over land than over water;
- More at high latitudes and in winter than at low latitudes or in summer;
- More at night than during the day.
What are the predicted evaporation changes?
Evaporation increases; but patterns of precipitation change:
Contrast between wet and dry regions and seasons will generally increase (to a first order, dry regions get drier, wetter regions will get more precipitation).
What are predictions dependent on?
Overall predictions are very dependent on scenarios → We can change the outcome.
What is an example of change that will take longer?
Some changes are expected to proceed more slowly and last considerably longer, such as for sea levels.
Even in scenarios where air temperatures stop rising beyond a certain level (e.g., 1.5°C), the slow mixing and warming of the oceans should lead to significant sea-level rises in a 1000-10000 yr horizon.
