In her introductory talk, Professor Joanna Haigh (Imperial College London) outlined the challenges that humanity faces in combating climate change and summarised the main factors contributing to an increase in the Earth’s temperature. Her talk illustrated the increase in the Earth’s temperature since 1850, the decrease in Arctic summer sea ice, the rising global average sea level, and the increase in the average ocean heat content. She emphasised that the physics of the greenhouse effect are simple and have been known since the 19th century.
There are few options to tackle climate change on the timescales required to limit the mean global temperature rise to below 2 °C, as stated in the COP 21 agreement in Paris 2015. Exceeding this level of temperature increase may cause dramatic changes in the Earth’s weather systems. The options are to adapt to the global impacts of global warming, to significantly reduce greenhouse gases emissions, and/or to use geoengineering. Geoengineering has been defined by the Royal Society as “the deliberate large scale manipulation of the planetary environment to counteract anthropogenic climate change.”
Geoengineering schemes can be divided primarily into land-, ocean-, atmosphere- and space-based approaches. Professor Haigh explained that, fundamentally, there are two different methodologies. The first aims to remove carbon dioxide (CO2) by physical or chemical means (carbon dioxide removal, CDR).