Lecture 13: Global Warming and Climate Change Quiz

Radiative Forcing

• Radiative forcing is the difference between the energy the Earth receives from the sun and the energy it loses to space
• Positive radiative forcing occurs when the Earth absorbs more energy from the sun than it loses to space, warming the planet
• Negative radiative forcing occurs when the Earth loses more energy to space than it receives from the sun, cooling the planet

Climate Models

• Climate models have uncertainties associated with them

Human Activities

• The two general components of human activity that most affect global warming are:
  • Burning of fossil fuels (releases CO2)
  • Deforestation (releases stored carbon into the atmosphere)

Greenhouse Effect

• The greenhouse effect is the process by which certain gases in the atmosphere trap heat from the sun, warming the planet
• Greenhouse gases include:
  • Carbon dioxide (CO2)
  • Methane (CH4)
  • Water vapor (H2O)
• The greenhouse effect was discovered by Joseph Fourier in 1827
• Svante Arrhenius predicted in 1896 that adding CO2 to the atmosphere would cause climate change

Paris Agreement

• The Paris Agreement aims to limit global warming to well below 2°C and pursue efforts to limit it to 1.5°C above pre-industrial levels

Physical Evidence of Global Warming

• Multiple lines of evidence show that the Earth is warming, including:
  • Rising global temperatures
  • Shrinking ice sheets
  • Glacier retreat
  • Rise in sea level
  • Shift in seasons

Physical Evidence of Human-Caused Global Warming

• Multiple lines of evidence show that humans are causing global warming, including:
  • Increase in global temperatures
  • Shrinking of Arctic sea ice
  • Shift in the timing of seasons

Effects of Increasing CO2 on the Ocean

• Increasing CO2 in the atmosphere leads to ocean acidification, harming marine life

Obtaining CO2 Values

• CO2 values for the atmosphere thousands of years ago can be obtained through ice cores and other natural archives

Human Responsibility for Added CO2

• The physical evidence that proves humans are responsible for the added CO2 in the atmosphere includes:
  • Isotopic signature of CO2
  • Increase in CO2 levels coinciding with human industrial activity

Dealing with Climate Change

• Humans will be forced to deal with global climate change in two basic ways:
  • Mitigation (reducing greenhouse gas emissions)
  • Adaptation (adapting to the changing climate)

Causes of Sea Level Rise

• The two main causes of sea level rise due to global warming are:
  • Thermal expansion of seawater
  • Melting of glaciers and ice sheets

Fossil Fuel Use

• Fossil fuel use goes mainly toward producing energy