Brent Cornell

    
Greenhouse gases play a pivotal role in determining global temperatures and climate patterns due to their capacity to retain heat

• As these gases trap heat, increases in greenhouse gas concentrations should correlate with an increase in global temperature 
• Long term weather patterns (climate) may also be influenced by greenhouse gas concentrations
  

Scientists predict that increases in greenhouse gas concentrations will lead to an enhanced greenhouse effect, resulting in:

• More frequent extreme weather conditions (e.g. heat waves, cyclones, more powerful tropical storms, etc.)
• Some areas to become more drought affected, while other areas become more prone to periods of heavy rainfall
• Changes to circulating ocean currents – which may cause longer El Nino (warming) and La Nina (cooling) events

    
The link between global temperatures and carbon dioxide concentrations was established by analysing data over a long time period

• Ice cores taken from the Vostok station in Antarctica provide evidence of the environmental conditions at the time of freezing
• The Vostok ice core is one of the longest drilled, reaching back 420,000 years and covering the past four glacial cycles
• By analysing the gas bubbles trapped in ice, historical CO₂ levels and air temperatures (via oxygen isotopes) can be deduced

Data collected from the Vostok ice core demonstrates that:

• There is a strong positive correlation between carbon dioxide concentrations and temperature (↑ CO₂ levels ∝ ↑ temperature)
• There have been fluctuating cycles of CO₂ concentrations which appear to correlate with global warm ages and ice ages
• Current concentrations of CO₂ are higher than at any time recorded in the last 400,000 years

Vostok Ice Core Data – Temperature versus Carbon Dioxide Concentration

    
The industrial revolution introduced new manufacturing processes which significantly increased mankind’s use of fossil fuels

• The burning of fossil fuels releases carbon dioxide as a by-product, leading to a steady increase in its atmospheric concentration

When fuel emissions, atmospheric CO₂ concentrations and global temperatures are compared, the following trends are revealed:

• There is a strong positive correlation between increasing fossil fuel emissions and rising atmospheric concentrations of CO₂
• Atmospheric CO₂ concentrations have increased ~38% since pre-industrial times (1800: ~ 280 ppm ; 2010: ~ 380 ppm)
• About 40% of CO₂ emissions have remained in the atmosphere, the rest has been absorbed by carbon sinks (mainly oceans)
• This increase in atmospheric carbon dioxide concentration correlates with an increase in average global temperature
• While correlation does not equal causation, there is mounting evidence to suggest that CO₂ emissions are linked to global temperature changes (although other factors likely also contribute)

Carbon Dioxide Emissions, Atmospheric Concentrations and Global Average Temperatures