Question

Which of the following are possible causes of global warming? Check all that apply.

human activity

differences in emitted energy from Earth

natural fluctuations

changes in distance to the Sun

poor measurement

Answer 1

Select: human activity — yes; differences in emitted energy from Earth — yes; natural fluctuations — yes.

Explain briefly:
- Human activity: burning fossil fuels, deforestation, etc., increases greenhouse gases and traps more outgoing long‑wave radiation, causing warming.
- Differences in emitted energy from Earth: if Earth emits less energy to space than it receives (due to greenhouse gases or changes in albedo), the planet warms.
- Natural fluctuations: things like volcanic eruptions, El Niño/La Niña, solar variability and long‑term orbital (Milankovitch) cycles can cause warming or cooling.

Changes in distance to the Sun: technically can change climate on very long (orbital) timescales, so it’s a possible natural cause historically, but it is not the cause of the recent global‑warming trend.

Poor measurement: not a cause of warming — it only affects how accurately we observe it.