According to the U.S. National Oceanic and Atmospheric Administration, the atmospheric concentration of CO2 has been increasing, global surface temperatures have increased about 0.2°C (0.4°F) over the past twenty-five years, and sea level has been rising 1 to 2 mm/yr since the late nineteenth century.

Describe what evidence you would look for to confirm these increases are due to human activity rather than changes in the Sun’s output or energy, or changes in Earth’s orbit.