TED: Why I must speak out about climate change | James Hansen

The speaker shares their journey from a scientist studying Venus to a climate change advocate. They discuss the greenhouse effect, early research findings, and the challenges faced in raising awareness. The talk highlights Earth's energy imbalance, feedback loops, and the urgent need for policy changes. Proposed solutions include a carbon fee to reduce CO2 levels and prevent further warming, emphasizing the importance of action for future generations.

What was the main finding about Venus that influenced the speaker's career?

• Venus is very hot due to a thick carbon dioxide atmosphere.

• Venus is extremely cold.

• Venus has a thick ionosphere.

• Venus has a high concentration of oxygen.

What did the 1981 paper predict about the 21st century?

• A stable climate with no significant changes.

• Shifting climate zones and rising sea levels.

• A reduction in greenhouse gases.

• A decrease in global temperatures.

How does adding CO2 to the atmosphere affect Earth's energy balance?

• It increases Earth's heat radiation to space.

• It reduces Earth's heat radiation to space, causing a temporary energy imbalance.

• It cools the Earth's surface.

• It has no effect on Earth's energy balance.

What evidence suggests that feedbacks are already beginning?

• The decrease in sea levels.

• The loss of mass in Greenland and Antarctica.

• The stability of ice sheets.

• The increase in global temperatures.

What is the potential impact of continued climate change on species?

• Increased biodiversity.

• Extermination of species, including the monarch butterfly.

• Stability in species populations.

• A decrease in extinction rates.

What is the estimated sea level rise if CO2 levels remain at 390 PPM?

• A decrease in sea level.

• An increase of at least 15 meters.

• A stable sea level.

• No change in sea level.

What is the proposed solution to address climate change?

• A gradual decrease in renewable energy use.

• A gradually rising carbon fee distributed to residents.

• Increased subsidies for fossil fuels.

• A reduction in government intervention.

What is the consequence of not taking action against climate change?

• A stable climate with no significant changes.

• An increase in global temperatures and extreme weather events.

• A decrease in sea levels.

• A reduction in greenhouse gases.

What analogy does the speaker use to describe the urgency of climate change?

• A calm ocean.

• A gentle breeze.

• A peaceful forest.

• A giant asteroid on a collision course with Earth.

What is the speaker's main call to action?

• To wait for natural climate cycles to stabilize.

• To communicate the urgency of climate change and its solutions.

• To continue using fossil fuels.

• To ignore climate change.