Human vs. Natural Factors

Are humans and/or natural factors mostly responsible for recent changes in climate?
Skeptic Claim to Debunk:The recent change in temperature is due mostly to natural causes and not human activity.

Skeptics’ Sub-claims:

  • The sun’s variability in energy output is the greatest causes of recent climate change.
  • It is caused by volcanic eruptions and El Niño.
  • CO2 is plant food and CO2 is not a pollutant.
  • There is no correlation between CO2 and temperature.
  • Human CO2 is a tiny percentage of CO2 emissions.
  • It is the sun. It is not us. It is El Niño.
  • Volcanoes emit more CO2 than humans.
Core Science Concepts Needed to Understand the Argument:
Difference between the natural and amplified greenhouse effect, Earth’s energy balance and radiative forcings, carbon cycle, natural causes, (Milankovitch Cycles, volcanic     eruptions, solar activity, ENSO), anthropogenic/ human causes (fossil fuel combustion, changes in land-Use, cement production), climate feedbacks, global climate models)