Statement of Resource Person, Myles Allen 24 October 2018 Substantive matters 8) The overall science of extreme event attribution is well summarised in the statement of Sophie Marjanac, dated 3rd August 2018. In my presentation, I will focus on elements that are specific to the Philippines context or otherwise complement Marjanac’s statement. 9) A key finding of the recent IPCC Special Report on 1.5°C (SR1.5) was that human-induced global warming has now reached 1°C (±0.2°C) relative to the period 1850-1900 which may be considered approximately representative of pre-industrial conditions (greenhouse gas emissions had already caused some warming by the late 19th century, but this was partly compensated for by the impact of a series of large volcanic eruptions around that time). Hence, given that our best estimated of the net impact of natural climate drivers on global temperature change over the 20th century is small, to a good approximation, all of the observed warming since 1850 can be considered anthropogenic, with about 80% of that warming due to carbon dioxide emissions. 10) A second key finding was that, based on the evidence available from current climate models and our understanding of the underlying theory, the probabilities of many potentially damaging extreme weather events, including heatwaves and short-duration extreme precipitation events, increase predictably with rising global temperatures. Hence this provides a basis for relating harm associated with extreme weather events with attributable changes in global temperature. 11) The recent paper by Ekwurzel et al demonstrated that it was possible to trace contributions to global temperature change and sea level rise to emissions generated by products sold by specific major corporations, providing a potential framework for the apportionment of responsibility for climate-related harm. 12) Emissions are assessed to be impacting the Philippines through rising sea-level and potential changes in risks of high winds and precipitation associated with tropical storms and typhoons. In my presentation, I will specifically address the attribution study led by Izuru Takayabu 14 which demonstrates how the size and impact of the storm surge associated with an extreme typhoon may have been exacerbated by anthropogenic climate change, although no change in the frequency of such events has yet been attributed to human influence. Signed: Myles Allen Date: 24 October 2018 At: Oxford, United Kingdom I. Takayabu et al “Climate change effects on the worst-case storm surge: a case study of Typhoon Haiyan”, Environ. Res. Lett. 10 064011, 2015. 14 3