Climate and Sustainability
90 flashcards by MentisLibrary
Understand the greenhouse effect, the carbon cycle, and the feedbacks that drive climate change, then the renewables, policies, and practices meant to address it. Sorts out net zero, offsets, mitigation, and adaptation.
- What is the greenhouse effect?
- The warming that results when atmospheric gases absorb outgoing infrared radiation and re-emit it back toward the surface
- What is the enhanced greenhouse effect?
- The additional warming caused by human emissions raising greenhouse gas concentrations above natural levels
- Which are the main greenhouse gases affected by human activity?
- Carbon dioxide, methane, nitrous oxide, and fluorinated gases
- What does global warming potential measure?
- How much heat a greenhouse gas traps over a given period compared with the same mass of carbon dioxide
- How does methane compare with carbon dioxide as a greenhouse gas?
- It traps far more heat per tonne, roughly 28 times as much over 100 years, but breaks down in about a decade
- What are the main human sources of methane?
- Livestock digestion, rice paddies, landfills, and leaks from oil and gas systems
- What is nitrous oxide's main human source?
- Nitrogen fertilizer use in agriculture
- What is the Keeling curve?
- The continuous record of atmospheric carbon dioxide measured at Mauna Loa since 1958
- Roughly how much has global average surface temperature risen since the late 1800s?
- About 1.2 to 1.3 degrees Celsius
- Why is a rise of about 1 degree Celsius a big deal?
- It is a global annual average, and it shifts the whole distribution so extremes become far more likely
- How do scientists know current warming is not caused by the Sun?
- Solar output has been flat or slightly declining since the 1980s while temperatures rose
- What are Milankovitch cycles and why do they not explain current warming?
- Slow variations in Earth's orbit and tilt that pace ice ages over tens of thousands of years
- What is a climate feedback?
- A process that amplifies or dampens an initial change in the climate system
- What is the ice-albedo feedback?
- Melting bright ice exposes darker ocean or land, which absorbs more sunlight and drives further melting
- Why is thawing permafrost a concern?
- It releases carbon dioxide and methane from organic matter frozen for thousands of years
- What is a climate tipping point?
- A threshold beyond which a part of the climate system shifts to a new state that is hard or impossible to reverse
- What is the Atlantic Meridional Overturning Circulation and why is it watched closely?
- The Atlantic branch of the ocean's overturning circulation, which transports heat northward and could weaken with freshwater input
- What are the two main causes of sea level rise?
- Thermal expansion of warming seawater and meltwater from glaciers and ice sheets
- What is ocean acidification and what causes it?
- The fall in ocean pH caused by seawater absorbing atmospheric carbon dioxide
- What is the carbon cycle?
- The continuous exchange of carbon between the atmosphere, ocean, land, living things, and rocks
- What is a carbon sink?
- A reservoir that absorbs more carbon than it releases
- Why does burning fossil fuels change the carbon cycle so much?
- It moves carbon that was locked in geologic storage for millions of years into the atmosphere in a few centuries
- What role does the slow carbon cycle play?
- Weathering of rock and burial of marine sediments move carbon between the atmosphere and the crust over millions of years
- What is a carbon footprint?
- The total greenhouse gas emissions caused directly and indirectly by a person, product, organization, or activity
- What are Scope 1, 2, and 3 emissions?
- Scope 1 is direct emissions, Scope 2 is from purchased energy, and Scope 3 is everything else across the value chain
- What is a life cycle assessment?
- A structured accounting of environmental impacts across a product's whole life, from raw materials to disposal
- What is embodied carbon?
- The emissions produced in making and transporting a product, before it is ever used
- What is the difference between mitigation and adaptation?
- Mitigation reduces or removes greenhouse gas emissions; adaptation reduces harm from changes already underway
- Give examples of climate adaptation measures.
- Sea walls, drought-tolerant crops, early warning systems, urban shade and cooling, and flood-resilient building codes
- What does resilience mean in a climate context?
- The capacity of a system to absorb shocks and recover function