Written by Maranda St John Nicolle – CCOW
Last week, after a final round of negotiations, Working Group I of the Intergovernmental Panel on Climate Change (IPCC) released the “Summary for Policy Makers” of its report on the scienctific basis for climate change (full summary; headline statements).
The report is clear and concise:
- “Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.”
- “Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.”
- “Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes. This evidence for human influence has grown since AR4 [the last report, published in 2007]. It is extremely likely [= 95 to 100%] that human influence has been the dominant cause of the observed warming since the mid-20th century.
- Looking to the future, the report offers four emissions scenarios, representing possible concentrations of carbon dioxide by 2100. Current concentrations breached 400 ppm in 2013, up roughly 80 ppm in 55 years. The most optimistic scenario, which would require significant cuts in emissions, places 2100 concentrations at 421 ppm. The remaining scenarios place it at 538 ppm, 670 ppm, and 936 ppm by the year 2100. Under all but the first of the emissions scenarios, “Global surface temperature change for the end of the 21st century is likely to exceed 1.5°C relative to 1850 to 1900”; it is likely to exceed 2°C for the two highest emissions scenarios and more likely than not to exceed 2°C for the second lowest. Warming will continue beyond 2100 under all scenarios except the lowest.
- Sea level rises of between .25m and .63m (about 1 to 2.4 feet) over and beyond the level from 1986 – 2005 are predicted by the end of the century (the worst-case emissions scenario would offer a higher rise), and seas will further acidify. Heat will also affect ocean circulation.
- “Extreme precipitation events over most of the mid-latitude land masses and over wet tropical regions will very likely become more intense and more frequent by the end of this century, as global mean surface temperature increases.”
- “Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond” To have a 66% certainty of limiting the warming caused by manmade CO2 emission to less than 2 degrees centigrade, we need to limit the cumulative manmade emissions to between about 0 and 1000 trillion tonnes of carbon (or 800 trillion tonnes to account for other non-CO2 forcings). We had already emitted roughly 531 trillions tonnes by 2011. Assuming no change in our trajectory of emissions, we would have used up our “carbon budget” within two to three decades. (see this post for a good explanation)
There are no surprises in the general gist of the message: global warming and changes in the climate system are real; humans are the dominant cause of recent warming; and we have a choice – we can either limit our emissions or keep the earth on a trajectory towards ever more dangerous impacts. The level of certainty about human influence is greater than in past reports, though. And the emphasis on the total amount of CO2 emissions as the vital factor is also new to an IPCC report, as is the presentation of a “carbon budget.” (It is not however, “new” generally – see the work of Myles Allen here, here, and here)
How as Christians can we respond to this report? CCOW will have more on actions in their forthcoming weekly emails. But in terms of prayer, please pray:
- in thanksgiving for the God-given intellectual gifts that have enabled scientists to understand the natural world and our impacts on it. Give thanks for the many scientists involved in writing and reviewing the IPCC report and for the truly global reach of their research.
- in thanksgiving for the clarity of the report’s warning. Pray that more and more people will be prepared to engage with the scientific evidence
- for all those who have already been affected by changes in climate systems
- that the report may foster genuine and productive discussion among individuals, businesses and governments on mitigation (reducing risks by means such as reducing emissions) and adaptation (managing the impacts of climate change)
- that this discussion will be informed by godly values and will aim to work out ways of j living within the capacities of creation that will be joyful, sustainable and equitable. At present the risk is that those who have contributed least to emissions will be left to deal relatively unaided with the worst of the impacts. Pray for climate justice.
- that discussion will lead to action and to genuine change at all levels. Give thanks for recent moves in the US to reduce coal plant pollution.
- that comfortable Christians in both wealthy and less wealthy countries will take the challenges of global warming as an inspiration to greater faithfulness in living the Gospel. Pray that:
- we will live our lives in ways that express thanksgiving for God’s gifts and are determined by love of God and neighbour.
- we will call for equitable frameworks that ensure that all people have enough to live with dignity
- we will learn contentment and challenge the prevalent materialism that leads to overconsumption and to exploitation of both people and planet.
Further Reading: The excellent Guardian blog of the report’s release and responses to it, CAFOD/CARITAS responses; What does the IPCC report mean for businesses and investors? (Guardian); Reporting from “Dot Earth” blog with a focus on gaps between science and policy (New York Times), Le Monde (which suggests IPCC may be too conservative), Wall Street Journal (good summary, and significant as the paper has been historically fairly cautious), Times of India, Nature.
Written by Maranda St John Nicolle – CCOW