Climate change 2013: The physical science basis and the human response needed

Climate change 2013: The physical science basis and the human response needed

José Ignacio García, SJ

The Intergovernmental Panel on Climate Change (IPCC) is a major effort by the scientific community to provide evidence to decision makers and the general public on the mechanisms and effects of climate change. This time, 259 authors from 39 different countries worked on voluntary basis, as it is the IPCC way of proceeding, to produce Climate Change 2013: The Physical Science Basis of the IPCC Fifth Assessment Report. This is the outcome of the Working Group I, a full report of more than 2,000 pages, the major findings of which are furnished in a Summary for Policymakers.

In a sense, we could say that the report does not bring huge novelties other than to confirm the previous IPCC reports and to add much more evidence to the major issues that the IPCC previously shared. The IPCC is very careful in the way its assertions are presented, and considers the strength of the available evidence (limited, medium or robust), the degree of agreement (low, medium, high), or the level of confidence (very low, low, medium, high, and very high).

In a similar way, the assessed likelihood of an outcome or a result is indicated using the following terms: virtually certain 99–100% probability, very likely 90–100%, likely 66–100%, about as likely as not 33–66%, unlikely 0–33%, very unlikely 0–10%, exceptionally unlikely 0–1%. Additional terms, such as extremely likely 95–100%, more likely than not >50–100%, and extremely unlikely 0–5%, were also used when appropriate.

What for some can be considered as an obscure way of presenting things, especially for the press that often looks for dramatic headlines, is a demonstration that the IPCC wants to keep a strong stand in its scientific contributions to the challenges of climate change. They are not replacing politicians nor civil society, as these are the stakeholders called to take decisions, but the IPCC is making an essential contribution in providing the evidence needed to move forward.

The IPCC does not do research itself. It is a collaborative work of hundreds of scientists that review the research produced in the last years on these topics and produce a broad assessment. The big difference between the previous Climate Change 2007 (IPCC Fourth Assessment Report) and the present is the amount of research developed within this period. Hundreds of universities and research centres oriented their activity towards climate change and related issues. Again, nothing totally new, but a stronger confirmation of the main alerts and indicators were proposed. The following is a quick description of the findings.

Global warming

It is now considered even more certain (> 95%) that human influence is the dominant cause of the observed warming since the mid-20th century. Natural internal variability and natural external factors (e.g. the sun) contributed virtually nothing to the warming since 1950.

The measured global temperature curve from several data sets (Top: annual values; Bottom: averaged values over a decade)
The future temperature development in the highest emissions scenario (red) and in a scenario with successful climate mitigation (blue) – the “4-degree world” and the “2-degree world

The last 30 years were probably the warmest since at least 1,400 years. The future warming by 2100 – with comparable emission scenarios – is about the same as in the previous report. For the highest scenario, the best estimate warming by 2100 is still 4 degrees C.

Sea level rise

Sea levels are rising faster now than in the previous two millennia, and the rise will continue to accelerate – regardless of the emissions scenario, even with strong climate mitigation. This is perhaps the biggest change over the 4th IPCC report: a much more rapid sea level rise is now projected (28-98 cm by 2100). This is more than 50% higher than the old projections (18-59 cm) when comparing the same emission scenarios and time periods.

Land and sea ice

Over the last two decades, the Greenland and Antarctic ice sheets are losing mass, glaciers continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover continued to decrease in extent.

In the new IPCC report, the critical temperature limit at which a total loss of the Greenland ice sheet will occur, is estimated as 1 to 4 degrees C of warming above pre-industrial temperature. With unabated emissions, the Arctic Ocean will likely become virtually ice-free in summer before the middle of the century. In the last report, this was not expected until near the end of the century.


The IPCC expects that dry areas become drier due to global warming, and moist areas even wetter. Extreme rainfall is likely already increasing in North America and Europe. Future extreme precipitation events are very likely to become more intense and more frequent over most land areas of the humid tropics and mid-latitudes.

Measured CO2 concentration and pH in seawater, with low pH meaning higher acidity


At high emissions, the IPCC expects a weakening of the Atlantic Ocean circulation (commonly known as the Gulf Stream system) by 12% to 54% by the end of the century. The CO2 emissions not only cause climate change but also an increase in the CO2 concentration in seawater, and the oceans acidify due to the carbonic acid that forms.

What do we do? The challenges of lifestyle change, more active civil society engagement, and adaptation

Scientists provide us with the best they can, now it’s the time for stakeholders (states, companies, NGOs, and civil society) to develop their views. As we have seen it is a most difficult and tricky game. Diplomacy and international institutions are in very bad shape (Copenhagen, Kyoto Protocol, just to mention the most visible failures), the financial crisis has become a nightmare for the real economy (unemployment, crusades to promote growth whatever the consequences), and the environment has been downgraded as an urgent concern in the public opinion polls.

The IPCC will produce several reports in 2014: the Working Group II report on socio economics aspects and adaptation by March, the Working Group III report on mitigation by April, and the final Synthesis Report, which is the most politically valuable as this will be approved by government representatives, is expected by October 2014.

At this stage, it is critical we focus attention and action on what the IPCC Fifth Assessment Report is also indicating beyond the scientific studies. One is that human activity is crucial in our current situation and that lifestyle changes and civil society engagement are imperative. The second is adaptation and which is the real challenge. As we go through the report, we can realize that the situation is very likely to change in a significant way. The challenge will be to adapt to new – and uneasier – conditions, a major challenge for individuals and communities.


2 thoughts on “Climate change 2013: The physical science basis and the human response needed

  1. Dear Des,
    It is lovely to hear from you and of a youth that is so familiar to me on the banks of the Shannon. As I moved over the years I also read Teilhard, Thomas Berry, Julian of Norwich, Al Fritz and … these are very important to us and perhaps a cosmic vision for youth in Europe. The struggle in Asia is hard, it is not that we don’t care but we suffer and suffer the burden of many other things going wrong. Consumerism plagues us and we loose the significance or relations.
    The answers for me though are in the youth. Yes blowing in the wind. For the youth here in Asia, I live amongst indigenous communities, the crunch is in identity; identity as a way of thinking and sharing and engaging that affirms them as who they are, and furthermore as the land they live on, their ancestors and the epics that link ancestors with the creator. The youth I am learning from here tell me about their dreams of having cell phones and motorbikes, actually much simpler things usually, the cheapest cell phone as a music player and motorbike long-sleeved shirts. But really deep down they talk of all kinds of insecurity often unable to face the world impinging on them and humbly the needs of their siblings to get to school.
    The world over there is job insecurity and need for relationships/belonging that are at the core of what youth are struggling with. For me the story begins with gratitude and a growing self awareness and reflection where the young women and men can express hope and desire that includes others. The drain to the cities in present globalization is inevitable, but the ability to return home is very important to us. I am struggling with a group of your as to how to keep the forest around the villages as source of life and stability (landslides all down the valley) the aesthetics, which is as much belonging as it is beauty, comes slowly, and the meaning of Creator comes even later down the line of reflection.

    I don’t know where you find a root in Ireland, music poetry, maybe the Milky Way if you can see it, but for us it is identity and relation of which the land and water are part, and scraping together a cultural value system that echoes this with a hope. So we start with gratitude, where we find it often in the quiet sharing of another, and where too we find hope in some collective way.

    As I wrote to a friend my day has been full, I was down the estero de San Miguel-Ligarda with about 150 families needing permanent housing, about five other esteros (waterways) in Metro Manila and then Baseco with 52,000 families needing housing by Manila Bay. I still have the presence of the widow of last Sunday’s gospel thumping in my heart, how long must we wait. I walked out through all the rubbish to the sandy shore created by a 200 million effort to reclaim for commercial development not housing, but the sea had claimed it back and the walls collapsed, becoming “Sunday by the beach” for hundreds of children and families, time out from a drudgery and so easily happy for a moment.

    We need prayers to continue this change in how government responds to relocation. I suppose the real saving grace is the smile of the children, seeing some of them with their exercise books writing out their lessons, the old lady at the door, the youth challenging yet together around a basketball hoop.

    I read a review of the three gorges dam and the miss use of money, more relocation and ecosystem loss, and the hopes. With climate change we have it all wrong, we must change; then I listened to Felix Diaz of the Qom and Pope Francis’ meeting them… while I listen to Alina played by Arvo Part.

    We have the earthquake in Bohol, 300,000 people with needs, and the future has to be rewritten as to what we must do, but I am deeply uplifted by the youth. Tonight we pray, and see what we can pick up together tomorrow. Now I am rambling and time to stop. Pedro

  2. Thank you José,

    I found this summary of the IPCC 5th Assessment Report very interesting and provocative. I suppose it’s main significance for me is the extent to which environmental change is driven by human activity. Also interesting is the estimate of the impact of the temperature rise on our climate and on the sea level changes. Thank you very much.

    I live at the other side of the world from you, in Ireland, on the western edge of the Eurasian land mass. So I suppose my interest in ecology, and particularly in the impact of human activities on the Earth’s well-being is different from yours. In East Asia I think you experience very directly the impact of climate change on the lives of people. It is much more immediate and drastic in its impact, than it is here in Ireland.

    Changing weather patterns are our main concern. I doubt that anyone here has been left without food, clothing or shelter through climate change yet. Nevertheless, the change in the weather is effecting farm income because of reduced yields or difficult harvests.

    I have been ‘ecologically aware’ ever since my childhood. I grew up in Dublin, the capital city of Ireland. But both my parents were from farming stock so I could spend my holidays on my grandparents’ farms. I loved it. I used spend ever minute of every day out on the land. I was enraptured by the big skies, the swirling, changing clouds, the thunder and lightning and the grand vistas. I also loved to explore the nooks and crannies of the farm and neighbouring lands. (A boy could wander wherever he wished in those days. I did, and I took it all for granted.) I was captivated and still love nothing better than a day or a month in the mountains. It is only a short drive from where I live in the city to the Dublin and Wicklow mountains. They are not large -about 40 X 20kms – but they are beautiful and inexhaustable in mystery. Indeed, without knowing what was happening, I was enraptured by the beauty of the mystery – a mystery I later I came to recognise as God.

    My mother loved to garden – we had a small flower and vegetable garden in Dublin – and I enjoyed being with her there. There I discovered the soil and the inhabitants of the soil and all the insects who inhabit the garden and share it with us. (Mind you, the snails were greedy and had to be kept in check!)

    All that is only by way of introduction, so let me go to my main point.

    The main issue prompting my writing today is exploring the motivation behind our concern as a Society for engaging in ecological issues. I write to you as one who know the motivation from your own experience. No doubt it is two-fold, religious and social, an element of our Christian and Jesuit option for the poor. Certainly my first interest in ecology as a Jesuit, apart from what might be called the aesthetic, was as part of our option for the poor. And I can see how relevant that option is for our work in so many parts of the world where the destruction of the environment has caused so much hardship and even so many deaths. Yet it does not seem an appropriate ground for a apostolate here in Ireland.

    Three years ago I celebrated my Golden Jubilee as a Jesuit. At the time I was engaged in pastoral work as a parish chaplain in a Dublin parish. I loved the work and was good at it, but was withdrawn from it to explore the possibility of setting up a spirituality centre in Limerick. The province had decided to close our Church in Limerick after well over a century and thought we might set up a spirituality centre in its place. In the end we decided against that, and I was left without a job! It was not long before a call came for a chaplain in a mental hospital. I was assigned to the work, and am still at it today. But my involvement with the proposed spirituality centre set off a train of thought that eventuated in considering getting involved in ecological issues. Out of that I started reading Eco-Jesuit and the papers in ‘Promotio Justitiae.’ But I could not find anything that I felt would ground an apostolate in Ireland. Reviewing the grounds of my own commitment to the integrity of the Earth I realised that it was rooted in the early experiences I described above, experiences that I only then fully appropriated as my own fundamental religious experiences. I had never thought of them as revelatory experiences before that! What a pity. Talking to a friend about the matter I was directed to the writings of Thomas Berry. (Teilhard de Chardin seemed a bit beyond me). In Berry I found a kindred spirit for whom the experience of the Cosmos is a religious experience revealing the heart of God and establishing an intimate religious motivation and direction for our ecological concern. I do not mean it replaces our current grounding of the ecological mission in our social concern and option for the poor. No, it only highlights the motivation already present. But it does activate my own ecological concern in a new and more intimate way, a way that I think might ground an ecological apostolate in the ‘First-World’ and maybe even add a perspective to Christian belief that would open the gospels anew to some people. Since you are already involved in ecological work I would be interested in your views and comments on my ramblings above or know of anyone whose work is grounded in the revelatory role of the Cosmos or in the writings of Thomas Berry.

    Your brother in Christ.
    Des O’Grady, S.J.

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