6 Session 8 summary

Media reporting of climate science can be emotive, and there is always a risk of evidence being misrepresented. It is important to investigate media claims in more detail: you found that climate models do not appear to be ‘wrong’, though they should be tested more thoroughly than with GMST alone.

Just as for climate change, public acceptance of geoengineering varies and is thought to be influenced by political and cultural views. ‘Lukewarmers’ generally consider climate change risks to be small or the proposed actions undesirable. One example of public opposition to geoengineering is the ‘chemtrail’ conspiracy theory, which posits that organisations are secretly distributing chemicals in the atmosphere for a variety of (undesirable) purposes.

The UNFCCC Paris Agreement aims to hold the increase in GMST to ‘well below 2 °C’ above preindustrial levels and to ‘pursue efforts’ to limit it to 1.5 °C. However, if we continue to follow the RCP8.5 scenario of very high greenhouse gas concentrations, there is a predicted one-in-two chance of exceeding 4 °C warming and, even under future pledges, global warming is predicted to be around 3 °C.

You have considered some of the different factors involved in making decisions about climate change (geoengineering, mitigation or adaptation). These include the range of predicted impacts, the inherent uncertainties, the difficulty in reducing changes in the complex Earth system to a simple GMST target such as the Paris Agreement, and the balancing of competing priorities. You have also reflected on the role of your own values in your views on decision-making in geoengineering and climate change.

The conclusion of this course, then, might be that there are no easy answers.