Evidence for Climate Change

• ICE CORES - tubes of ice drilled from Arctic + Antarctic ice caps, see gases trapped in ice, lots of CO2 = earth was warmer, can date back 800000 years
• TREE RINGS - each ring is one year of growth, wider rings = warmer + wetter climate because tree grew faster, can date back 13000 years
• GLOBAL TEMPERATURE DATA - global temp has been collected since 1850, temp records are reliable but older data was on older + less accurate equipment
• SHRINKING GLACIERS + MELTING ICE: since 1979 scientists have taken photos of Arctic sea ice, evidence is reliable but does not extend over a long period of time