Evidence for Global Climate Change

Question 1

Evidence over geological time - Ice Cores

Answer 1

• Ice is the only environmental data available for scientists to reconstruct the climate from thousands of years ago. Scientists obtain ice cores by removing a cylindrical tube many metres long, which can provide data going back over 800 000 years
• Bubble trapped within the ice capture the gas concentration of our atmosphere, while the ice itself contains distinct layers from the snow that has fallen
• Ice cores can tell scientists about past temperatures, precipitation, CO2 levels, volcanic activity and wind patterns

Question 2

Evidence in recent human history- The atmosphere

Answer 2

• The last few decades have been successively warmer than any preceding decade since 1850 when measurements begun
• Globally, 19 out of the 20 hottest years ever recorded have occurred since the year 2000
• The average surface temperature of the Earth has increased by 1.1C in the last 100 years, with most of this warming since the 70’s
• Australia has warmed by a higher rate than the global average (1.4C in 100 years), resulting in repeat record-breaking high and average temperatures. In January 2022 Perth recorded six consecutive days with maximum temperatures of at least 40C, setting a new all time record
• These increased temperatures are a direct result of the increased concentrations of greenhouse gasses in our atmosphere. The global CO2 concentration is almost 50% higher than pre-industrial conditions