I was asked to serve as an expert witness for a December trail of an Extinction Rebellion activist who was arrested on Waterloo Bridge during the April 2019 actions. I was both keen to submit documents to the court and very concerned that I do my best to accurately and concisely represent a potentially very large body of research. I was assisted by Prof Richard Betts, University of Exeter, and Prof Rebecca Willis, University of Lancaster. They did not review my statement and any errors or omissions in the statment below are entirely due to me.
I offer this statement in the hope that it could perhaps start a process whereby we could collect witness statements in such trials in order that we can help improve future statements. The statement can be downloaded in PDF format HERE.
Expert Witness statement for the trial of Ms Anne-Marie Culhane: Current and future impacts of environmental change
Dr James Dyke
Details of the expert’s qualifications, relevant experience and accreditation
I am an Assistant Director of the Global Systems Institute, and Programme Director of MSc Global Sustainability Solutions, at the University of Exeter. I am a Visiting Fellow in the School of Geography and Environmental Science at the University of Southampton where previous to my appointment at Exeter I was an Associate Professor of Sustainability Science. Previously I was a research scientist at the Max Planck Institute for Biogeochemistry, Jena, Germany where my research focussed on planetary system evolution. In 2017 I was a Visiting Researcher at the Earth-Life Science Institute at the Tokyo Institute of Technology. I am a fellow of the Royal Society of Arts, a member of the European Geosciences Union, and serve on the editorial board of the journal Earth System Dynamics. I hold a DPhil in Informatics and MSc in Evolutionary & Adaptive Systems from the University of Sussex. My research interests centre around exploring how life, and in particular humans, affect local to planetary-scale processes. I have conducted research into the identification and warning of potential tipping points in natural and social systems.
Introduction
The impacts humans are having on the Earth’s climate system are arguably the most studied phenomena in all of science. Nearly 200 international scientific organisations, including the Royal Society of the United Kingdom, hold the position that climate change has been caused by human actions. Through the burning of fossil fuels and changing land use such as deforestation, humans have within two centuries affected the energy balance of the climate system. This has trapped more heat in the lower portions of the Earth’s atmosphere, land masses and oceans. Since pre-industrial periods the average global ocean and land surface temperature has increased by 1.1°C.
In 2016, the United Nations Framework Convention on Climate Change established the Paris Agreement in which nations would coordinate their actions so that global warming was limited to well within 2°C, while striving to stabilise temperatures to no more than 1.5°C. The United Kingdom along with 196 nations signed the Agreement. While the international community has determined that 2°C above pre-industrial periods represents “dangerous climate change”, it is expected that there will be significant increases of risk of significant harm as warming continues to 1.5°C1.
Human impacts on the Earth system are not limited to the climate. Due to land use change, the introduction of invasive species and predation by humans, the biosphere is currently experiencing rates of species loss unprecedented for tens of millions of years2. As well as a marked reduction in the total number of species, there has also been significant decline in wild animal populations. There are credible estimates that the average size of wild vertebrate populations have declined by 60 percent over the past 50 years3.
Climate change will interact with biodiversity loss in complex ways4. It has been estimated that up to one in six of all species is threatened with extinction if global warming continues at its current trajectory5. As well as the amount of warming, the speed at which this warming occurs will be critical in determining if species are able to adapt to changing environmental conditions. It is expected that beyond 2°C tropical coral reefs will markedly decline, as they already shows signs of serious stress. Ecosystems such as the Amazonian tropical rain forest which are already stressed via increased fragmentation due to land use change will be subject to further impacts from increased volatility in rainfall and temperature6. The loss of a significant fraction of the Amazonian rainforest has the potential to produce global reinforcement of global warming and thus further biodiversity loss.
A number of tipping elements in the climate system have been identified7. Proposed tipping elements in the global climate system include the Amazon tropical rainforest, tropical coral reefs, Arctic sea ice, the Greenland ice sheet and ocean currents. There is currently significant uncertainty as to what magnitude of global warming will initiate these tipping elements. Once a tipping element is activated is it expected to produce a series of runaway processes that would amplify the original driver. Recent research concluded that the interaction of tipping elements could force the climate system into a trajectory towards hothouse conditions that would represent an existential threat to human civilisation8.
In 2018, global emissions of greenhouse gasses increased at a rate higher than the previous seven years. Current policies relating to greenhouse gas emissions are projected to lead to global warming of between 2.5°C and 4.4°C relative to the pre-industrial state by 21009. It is expected that this warming will continue into the next century.
Potential harm from environmental change
An international study coordinated by University College London and the medical journal Lancet in 2009, concluded that human-caused climate change was responsible for 5.5 million disability adjusted life years (DALYs) lost in 200010. It was noted that this initial assessment was conservative and related only to deaths caused by cardiovascular diseases, diarrhoea, malaria, accidental injuries in coastal floods and inland floods or landslides and malnutrition. Their methods showed that small increases in the risk for climate-sensitive conditions, such as diarrhoea and malnutrition, could result in very large increases in the total disease burden.
A 2019 update to this report11 include worrying global developments:
“Downward trends in global yield potential for all major crops tracked since 1960 threaten food production and food security, with infants often the worst affected by the potentially permanent effects of undernutrition… Children are among the most susceptible to diarrhoeal disease and experience the most severe effects of dengue fever. Trends in climate suitability for disease transmission are particularly concerning, with 9 of the 10 most suitable years for the transmission of dengue fever on record occurring since 2000… Similarly, since an early 1980s baseline, the number of days suitable for Vibrio (a pathogen responsible for part of the burden of diarrhoeal disease) has doubled, and global suitability for coastal Vibrio cholerae has increased by 9·9%.”
Hotter conditions will increase heat stress. The internationally used measure for heat stress is Wet Bulb Globe Temperature (WBGT). A WGBT of 35°C is considered an “extreme” risk to health for physical activity outdoors. It has been estimated that a local warming of 3°C would cause the 5-day mean WBGT to exceed the “extreme” threshold for approximately 50% to 80% of the time in summer in regions of moderate or high humidity such as the south-eastern USA, the Caribbean, India, south-eastern China and northern Australia12. A local warming of 5°C increases this to approximately 80% to 95% of the summer.
2°C global warming is projected to lead up to an additional 82 million people per year being affected by river flooding13. 4°C global warming would increase this up to 269 million people per year more than the present day.
The IPCC 5th Assessment Report14 projected that by 2100, global average sea levels will increase between 0.2m and 0.6m in a scenario in which global temperatures are stabilised at around 2°C warming. In a scenario of 3°C to 6°C global warming, sea levels are projected to rise between 0.5m and 1.0m by 2100, or several tens of centimetres more if some areas of ice sheets collapse. It has been calculated that a sea level rise of 0.5 metres by 2100 would cause approximately 72 million people worldwide to be affected by coastal flooding at least once a year15. It has been estimated that a 2-metre sea level rise would affect 187 million people.
United Kingdom’s actions on climate change
The United Kingdom introduced internationally leading legislation in 2008 with the Climate Change Act. This mandated future governments put in place the necessary policies to ensure that UK greenhouse gas emissions in 2030 were 80% lower than 1990 levels. The independent Committee on Climate Change (CCC) was created by the Act in order to provide advice to the UK Government on achieving the 2030 target.
In the UK, greenhouse gases are emitted from power generation, industry, transport, buildings (commercial and residential) and agriculture. The Government is able to reduce these sector emissions via a range of policies. The CCC publishes annual progress reports. The 2019 report concluded that the UK Government was significantly behind the 2030 target having implemented only one of the 25 recommendations that the CCC made in its previous report16. In some cases the UK Government has actually cancelled emission-reduction policies introduced by previous governments. The Government is not on track to meet the 2030 targets. For example, emissions from buildings were up 3% up on last year, with aviation seeing a 3.5% annual increase.
In order for the UK to meet its international obligations as part of the efforts to limit warming to no more than 1.5°C, much more strident policies are required. This would go beyond the recently declared ambition for the UK to be ‘net-zero’ by 2050. Policies in accordance with the terms of the Paris Agreement may require this date to be brought forward to 2025. This would involve significant changes to most sectors of society given the existing prevalence of fossil fuel use in the UK. There are currently no discussions in Government as to how such a very rapid process of decarbonisation would be effected.
References
- IPCC, 2018: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, et al (eds.). 2019.
- Ceballos, G., Ehrlich, P.R., Barnosky, et al, 2015. Accelerated modern human–induced species losses: Entering the sixth mass extinction. Science advances, 1(5), p.e1400253.
- Grooten, M. and Almond, R.E.A., 2018. Living planet report–2018: Aiming higher. WWF, Gland, Switzerland, pp.22-100.
- Steffen, W., Richardson, K., Rockström, et al, 2015. Planetary boundaries: Guiding human development on a changing planet. Science, 347(6223), p.1259855.
- Urban, M.C., 2015. Accelerating extinction risk from climate change. Science, 348(6234), pp.571-573.
- Lovejoy, T.E., Nobre, C. Amazon Tipping Point Science Advances Vol. 4, no. 2, DOI: 10.1126/sciadv.aat2340.
- Lenton, T.M., Held, H., Kriegler, et al, 2008. Tipping elements in the Earth’s climate system. Proceedings of the national Academy of Sciences, 105(6), pp.1786-1793.
- Steffen, W., Rockström, J., Richardson, et al, (2018) Trajectories of the Earth System in the Anthropocene. Proceedings of the National Academy of Sciences (USA), DOI: 10.1073/pnas.1810141115.
- Climate Analytics https://climateactiontracker.org/.
- Costello, A., Abbas, M., Allen, et al, 2009. Managing the health effects of climate change. The Lancet, 373(9676), pp.1693-1733.
- Watts, N., Amann, M., Arnell, N. et al, 2019. The Lancet Countdown on health and climate change: ensuring that the health of a child born today is not defined by a changing climate. DOI:https://doi.org/10.1016/S0140-6736(19)32596-6.
- Willett and Sherwood, 2012. Exceedance of heat index thresholds for 15 regions under a warming climate using the wet-bulb globe temperature. Int. J. Climatol. 32: 161–177 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.2257.
- Alfieri, L., et al. (2017) “Global projections of river flood risk in a warmer world” Earth’s Future https://agupubs.onlinelibrary.wiley.com/doi/full/ 10.1002/2016EF000485.
- Church, J.A. et al. (2013) Sea Level Change. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., et al. (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA https:// www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter13_FINAL.pdf.
- Nicholls, R.J. et al. (2010) Sea-level rise and its possible impacts given a ‘beyond 4°C world’ in the twenty-first century Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 369, http://doi.org/10.1098/rsta. 2010.0291.
- Committee on Climate Change 10 July 2019 http://www.theccc.org.uk/publications.
