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Climate Change & its Impacts

Credit: ‘Climate change is in our hands’ by Stephanie Flude (distributed via

The Earth is warming due to an increased quantity of greenhouse gases (GHGs) being emitted into the atmosphere. Carbon dioxide, methane, nitrous oxides, and fluorinated compounds are the major substances which contribute to this effect. Their major sources, as well as other contributors to climate change, are listed below:

  • The industrial (21%), energy (35%) and transportation (14%) sectors all burn coal, oil and gas which releases GHGs into the atmosphere.
  • Agriculture is a large source of methane (livestock) and nitrous oxide (fertilizers). Agriculture, Forestry and other land-use make up 24% of all global GHG emissions.
  • Fluorinated gases whose sources include refrigerants, aerosol propellants, solvents, and fire retardants, as well as some industrial processes, have a much larger warming effect than carbon dioxide. Their emissions are relative low compared to the other major GHGs.
  • Deforestation adds to the GHG effect by stopping a process which removes carbon dioxide from the atmosphere. Additionally, the stored carbon dioxide within the trees themselves are released back into the atmosphere.
  • Aerosols, whose sources include industry, agricultural burning and volcanoes, have both a warming and cooling effect on the world’s climate. They also have a negative impact on air quality.

Effects of climate change:

The global effects of climate change are wide-ranging and dependent on the level of warming. Some research has shown that a small warming (1-3 °C by 2100) can have a positive impacts on some areas of the world and negative on others. More negative impacts throughout the globe will occur with increased warming. If global emissions continue to rise at current rates the world will be ~5 °C warmer by 2100. This is roughly the same temperature difference between present day readings and the last ice age (~12,000 years ago). Current and future climate change effects include:

  • Sea level rise
  • An increase in the number and severity of extreme weather events
  • Decreased frost periods
  • Increased growing periods in the higher latitudes
  • Changes in global precipitation patterns
  • An increase in the number and severity of droughts
  • A potentially ice-free Arctic

Current EU policy:

EU emissions represent about 10% of total global GHG emissions. In October 2014, the EU proposed legislation which included a 40% reduction in GHG emissions compared to 1990 levels by 2030. Renewable energy should make up at least 27% of energy production and there will be a 27% minimum improvement to energy efficiency.

The EU already has extensive climate change legislation which cover (among others) greenhouse gas monitoring, the EU emissions trading scheme, carbon capture policies, and transportation/fuel legislation. In light of the Paris COP21 meeting, these policies must be strengthened and maintained to ensure the agreement objectives can be met.

Future challenges:

The regulation and monitoring of emissions must continue to ensure the EU is meeting its legal requirements. Delaying mitigation action now increases future mitigation costs as more extreme steps will be necessary to produce the same results. In addition, further research must be conducted increase science’s understanding of the world’s natural mechanisms, their feedback systems and the impact human activity is having on these processes. Climate modelling must also be developed to give an improved understanding of the regional impacts a changing climate has to support potential mitigation and adaptation policies.

EGU climate change research areas:

  • Future scenario climate modelling (representation concentration pathways – RCPs)
  • The Earth’s past climate
  • Geoengineering strategies and their implications
  • New measurement techniques for GHGs
  • GHG emissions inventories
  • Mitigation and adaptation strategies
  • Natural variability / Earth processes
  • Adaptation co-benefits i.e. improved air quality studies

Recent EGU papers:


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