Intro to Climate Change Exam 3

please dont fuck this one up

What has happened to global average temperatures over recent decades?

They have increased significantly, with each of the past four decades warmer than the one before it.

What are the general temperature projections for Pennsylvania and Pittsburgh by mid‑century?

Continued warming, with more extremely hot days and higher average annual temperatures.

Name two major climate change indicators besides temperature

Rising sea levels, shrinking ice sheets, ocean warming, or increased frequency of extreme weather events

What is the “take‑home message” about recent climate trends across Earth’s spheres?

All major spheres (atmosphere, hydrosphere, cryosphere, biosphere) show clear signs of warming‑driven change

Why are myths about climate change considered myths?

They contradict scientific evidence, rely on misunderstandings, or misrepresent data.

What long‑term trend has been observed in Arctic sea ice extent?

It has been decreasing for decades, with summer minimums shrinking significantly.

Why is Arctic ice loss considered a strong indicator of climate change?

Because it responds quickly to warming and amplifies warming through the albedo effect

How do Antarctic ice trends differ from Arctic trends?

Antarctic sea ice shows more regional variability, but land‑based ice sheets are losing mass overall.

What is the “take‑home message” about cryosphere changes?

Ice is declining globally, contributing to sea level rise and signaling rapid climate system changes

How does melting land ice differ from melting sea ice in its impact on sea level?

Melting land ice raises sea level; melting sea ice does not significantly change sea level.

What are the two main contributors to global sea level rise?

Thermal expansion of warming ocean water and melting land‑based ice (glaciers + ice sheets).

Why does thermal expansion cause sea level to rise?

As water warms, it expands in volume, increasing sea level even without added water.

What long‑term trend has been observed in global sea level?

Sea level has been rising steadily, with the rate accelerating in recent decades

What is the AMOC, and why is it important?

The Atlantic Meridional Overturning Circulation; it transports heat and influences climate patterns

How is climate change affecting the AMOC?

Freshwater from melting ice and warming oceans may weaken it, disrupting heat transport.

What is the “take‑home message” about ocean changes?

Oceans are warming, rising, and shifting circulation patterns — all major signals of climate change

Where is the ozone layer located, and what does it do?

Located in the Stratosphere, composed of O3, protecting the earth from harmful UV rays from the Sun.

What chemicals were primarily responsible for ozone depletion?

Chlorofluorocarbons (CFCs) and related compounds.

How do CFCs destroy ozone?

UV light breaks CFCs apart, releasing chlorine atoms that catalytically break down ozone molecules

Why was the ozone hole especially severe over Antarctica?

Polar stratospheric clouds form in extreme cold, enabling reactions that activate chlorine and accelerate ozone loss

What was the Montreal Protocol?

A 1987 international agreement to phase out ozone‑depleting substances like CFCs.

Why is the Montreal Protocol considered a major environmental success?

It achieved near‑universal participation, rapidly reduced CFC emissions, and allowed ozone recovery to begin

What “take‑home message” can be learned from the Montreal Protocol?

Global cooperation, clear science, and strong policy mechanisms can successfully address environmental crises.

What is the UNFCCC?

The United Nations Framework Convention on Climate Change — the international treaty guiding global climate negotiations.

What is a COP?

A “Conference of the Parties,” the annual meeting where countries negotiate climate agreements under the UNFCCC

What were the main goals of the Paris Agreement (COP21)?

Limit warming to well below 2°C, pursue efforts to stay under 1.5°C, and strengthen global climate resilience.

What made COP21 unusually successful at the time?

Broad global participation, nationally determined contributions (NDCs), strong diplomacy, and flexible, country‑driven commitments

Why were NDCs important for COP21’s success?

They allowed each country to set its own emissions targets, making agreement politically feasible

What were some post‑COP21 setbacks?

US pulled out in 2025, marking a major setback, as the US is one of the highest emitters on the planet — set a precedent of lacking participation in subsequent nations.

What is the “take‑home message” from COP21?

Global cooperation is possible, but long‑term success depends on sustained political will and stronger emissions reductions.

What is the purpose of the Clean Air Act?

To regulate air pollutants harmful to human health and the environment through national standards and enforcement mechanisms.

Why was the Donora Smog event historically important?

The deadly 1948 smog in Donora, PA highlighted the dangers of industrial air pollution and helped motivate modern air‑quality regulation.

What caused the Great London Smog of 1952?

Cold weather, coal burning, and stagnant air trapped pollutants, creating a toxic smog that caused thousands of deaths

What are the two major categories of air pollution sources?

Stationary sources (factories, power plants) and mobile sources (cars, trucks, buses).

What is a cap‑and‑trade program?

A system where a limit (“cap”) is set on total emissions, and companies can buy or sell allowances to meet their targets.

Why is cap‑and‑trade considered effective for pollution reduction?

It provides flexibility and economic incentives for companies to reduce emissions efficiently.

What is RGGI?

The Regional Greenhouse Gas Initiative — a cooperative cap‑and‑trade program among northeastern U.S. states targeting CO₂ emissions from power plants. Seen massive success in states that have implemented it.

What is PACER in the context of Pennsylvania climate policy?

A proposed Pennsylvania carbon‑pricing program intended to function similarly to RGGI. Stalled in Pennsylvania legislature for the past few years.

What is the “take‑home message” about U.S. climate policy?

Progress is uneven, but regulatory tools like the Clean Air Act and cap‑and‑trade can significantly reduce pollution when implemented effectively.

What is the purpose of the “Global Warming’s Six Americas” framework?

To categorize the U.S. public into six groups based on their beliefs, concern, and engagement with climate change.

What are the Six Americas categories?

Alarmed, Concerned, Cautious, Disengaged, Doubtful, and Dismissive

Why is the Six Americas model useful for climate communication?

It helps tailor messages to different audiences based on their values, knowledge, and level of concern.

What is a key communication strategy for the “Alarmed” group?

Provide actionable steps and reinforce efficacy — they already accept the science and want solutions

What is a key communication strategy for the “Concerned” group?

Emphasize relevance and urgency, helping them move from awareness to action

What is a key communication strategy for the “Cautious” group?

Focus on clear, simple explanations and avoid overwhelming detail.

What is a key communication strategy for the “Disengaged” group?

Connect climate change to everyday experiences and local impacts

What is a key communication strategy for the “Doubtful” group?

Emphasize economic, health, or community benefits rather than scientific arguments

What is a key communication strategy for the “Dismissive” group?

Avoid confrontation; focus on shared values or shift to non‑climate topics where cooperation is possible

What is one general principle of effective climate communication?

Meet people where they are — tailor the message to their values, identity, and level of engagement.

Why is emphasizing co‑benefits (like health or jobs) effective in climate communication?

It appeals to broader motivations and reduces ideological resistance.

What is the “take‑home message” of climate communication research?

Effective communication depends less on facts alone and more on trust, values, and audience‑specific framing

What are some common myths related to climate change?

• It is too late // too difficult to combat climate change

• The sun’s solar cycles are causing changes in the climate

• Climate scientists are in it for the money — especially those working in IPCC and the NCA

• CO2 was higher in the past

Why is it not too difficult // too late to combat climate change?

The stabilizing wedge system outlined by Pacala and Socolow in 2004 estimates that if we shift to more renewable sources of energy, alongside minimizing unnecessary emissions, humanity can reduce our carbon output by many orders of magnitude.

Why aren’t the sun’s cycles responsible for modern climate change?

While orbital patterns can contributed to the Earth’s climate patterns in the past, the recent unprecedented warming of the Earth cannot be explained by orbital forcings alone. Earth’s modern climate can ONLY be explained by taking into account human influences.

Why is saying the CO2 was higher in the past a misleading claim when referring to modern climate change?

Modern rise in CO2 and subsequent temperature is unprecedented in Earth’s history. While CO2 levels were higher in prior periods of Earth’s history, humans did not live through this period. Furthermore, Humans rely on a stable climate. The 50% increase in CO2 levels over the past 150 years is too drastic to adapt to.

Why aren’t climate scientists, especially those of the IPCC and NCA, in it for the money?

Climate scientists are apart of a rigorous, evidence-based scientific process. Major assessments are built on broad collaboration, peer review, and transparency, not personal profit. The IPCC and NCA summarize existing research — they do not create their own data or push agendas.