Wednesday, April 18, 2018

Reflections on the Citizens Assembly consideration of climate change

The final report from the deliberations of the Citizens' Assembly on How the State can make Ireland a leader in tackling climate change is now available and delivered to the Oireachtas (and to our non-Irish readers, yes, whenever the political institutions of Ireland are discussed there is indeed a hint of Lord of the Rings). That means I am now allowed, apparently, to discuss this as a member of the Expert Advisory Group (other members were: Anna Davies, Margaret Desmond, John Garry, Aine Ryall, and Diarmund Torney).

The Citizens' Assembly is an exercise in deliberative democracy. There are people far more qualified than I to provide a definitive outline of what that is. But, at its most basic, it is picking randomly from those eligible to vote and bringing them together to hear evidence, discuss and then vote on issues within their charge. The Citizens' Assembly has considered 5 topics of which climate change was the third.

The assembly members were given two weekends to discuss the issues and then vote on a series of resolutions. The role of the Expert Advisory Group was to aid the Chair and secretariat to shape these deliberations. I got to know how to get to Government buildings rather well.

What were the key issues?

Finding the angle: The scope given was very broad and could have been taken in any number of directions. At the same time there were existing national activities around the national mitigation and adaptation planning and several existant bodies.  Ultimately, the citizens wanted to know what would change in their lives were Ireland to become a climate leader. So, the final structure was to spend the first day as a scientific primer and scene setting and then dive into the three major sectors of energy, transport and agriculture. Each sector should show what the status quo is, what 30 years hence may look like with leadership and take examples of how we are currently doing (ideally drawn from Irish exemplars).

Finding the right mix of speakers: Citizens needed to hear from speakers who could speak to the range of issues objectively. This was a challenging and rewarding puzzle to help solve. Particularly important was to hear inspirational examples of actual leadership in the here and now.

Helping find questions that answer the charge: The charge was how the State can make Ireland a leader so questions needed to be cast in the context of legal frameworks, incentives, policy and taxation. Questions needed to be realistic and recognise the need for trade-offs (no questions enabling having one's cake and eating it), and most importantly of all actionable.

The weekends themselves were fascinating. I'd urge people to look at the video presentations to see what was presented to the citizens. The citizens really engaged thoughtfully with the issue and asked challenging questions.

The final voting was very strongly (>80% in all cases) for a range of policy and fiscal measures which, if enacted in full would, indeed, make Ireland a leader in tackling climate change.

What happens next? Well, that, ultimately is up to members of the Oireachtas to decide. The report contains a wealth of information for their consideration.

It was a tremendous honour to serve the Assembly on this topic. It took me somewhat outside my comfort zone quite often but it was a real privelige to see the process in action and work with experts I wouldn't ordinarily interact with. The Chair and secretariat did sterling effort, but most of all the citizens impressed me with how much they engaged.

It is just a pity that this level of civic engagement is so much the exception rather than the norm in our modern democracies. When our governments do not care because we do not care or don't wish to become informed we quite frankly get the governments we deserve. Exercises such as the Citizens' Assembly offer a tantalising glimpse of an alternative.

Wednesday, January 10, 2018

The Atlantic Overturning Circulation and Ireland


Palm trees in Sligo

Figure 1:  Palm trees grow in Mullaghmore in Sligo (left), which is as far north as glaciated Grytviken, South Georgia (right) is south, where glaciers grow.[image modified from:Wikipedia]

Sometimes it’s easy to forget how far north Ireland is. Palm trees grow in Sligo on the northwest Atlantic coast whereas glaciers---though in retreat ---overshadow Grytviken, South Georgia (Fig. 1). Grytviken is as far south as Sligo is north, so why the big difference? 

Frequently people will cite the Gulf Stream as the reason for Ireland’s mild climate. This is an idea dating back to Matthew Fontaine Maury who coined the idea that the Gulf Stream was responsible for Europe’s mild climate in 1855. But the Gulf Stream itself is not inherently unique. It is an ocean current, called a ‘Western Boundary Current’ due to its location in the western North Atlantic, analogues of which exist in every major ocean basin. In the North Pacific, the Kuroshio is a western boundary current just as vigorous as the Gulf Stream. But when we look at surface temperatures relative to relative to the average for that latitude (Fig. 2), the Atlantic does stand out as anomalously warm.

Figure 2: Deviations from zonally averaged temperatures based on NCEP/NCAR reanalysis (annual mean) in degrees Celsius.[image: Joel Hirschi, NOC]

Atlantic Exceptionalism

The ocean process that drives the anomalous warmth in the Atlantic is the Atlantic Overturning Circulation. This is a system of currents that carries warm water northwards, through the Gulf Stream and its extended current, the North Atlantic Current. This water is warm and salty. As it loses heat, through a variety of processes, it forms deep, cold water that returns southwards. This exchange of warm and cold water leads to the largest movement of heat by any ocean. This heat is then released from the Atlantic and is carried by the prevailing winds over northwest Europe. This combination of ocean and wind is the reason for the exceptionally mild climate of northwest Europe.

Figure 3: Dublin is around 9C warmer than St Johns in Newfoundland and 4C warmer than the similar maritime climate of Seattle on the Pacific Northwest.[image from McCarthy et al., 2015, Weather]

The combination of winds and ocean is important and leads to a subtlety in discussing this Atlantic Exceptionalism. It might be tempting to look across from the cliffs of Moher in winter to the frigid Labrador coast of Canada and ascribe the almost 10 degrees C difference in temperature to the Atlantic Overturning. However, much of this temperature difference is due to this coast being downwind of the frigid Canadian landmass whereas Ireland is downwind of the ocean. A better comparison to reveal the impact of the Atlantic overturning on climate is to compare Ireland to similar maritime climates of the Pacific northwest. Dublin is 4C warmer than Seattle in winter and this difference can be mainly ascribed to the influence of the Atlantic Overturning Circulation. While not as dramatic a comparison as with the coast of Labrador, a mean difference of 4C is approximately the difference in temperature between the climate of Ireland and the climate of Northern Portugal.

Threats to the Overturning Circulation

The Atlantic Overturning has changed in the past, with large fluctuations in climate in the last glacial period associated with collapsing and recovering of the Overturning circulation, and it is predicted to decline in the future---the Intergovernmental Panel for Climate Change ranking as 'very likely' that the Overturning Circulation will weaken by 30% in the coming century.  If the overturning declines, this will have a serious impact on Irish climate. Evidence for a declining overturning is already mounting. Temperatures globally continue to rise due to anthropogenic global warming but, in the North Atlantic, a cold spot appears where a small temperature fall is occurring. 

Here at ICARUS, work is ongoing to understand the ongoing changes in the Atlantic, including understanding the drivers and the impacts that has on Ireland, northwestern Europe and beyond.

Figure 4: Global surface temperatures show a general increase due to anthropogenic climate change. A blue area in the North Atlantic shows where temperatures have not risen and could be indicative of a slowdown in the Atlantic Overturning Circulation.

Leagan Gaeilge

Crainn phailme i Sligeach

Is fusa dearmad a dhéanamh ar cé chomh fada thuaidh is atá Éire. Fásann crainn phailme i Sligeach ar an gcósta thiar ó thuaidh. Ar an leithead céanna, i nGrytviken, sa tSeoirsia Theas (Fig. 1), feictear oighearshruthanna, cé go bhfuil siad ag cúlú de bharr athrú aeráide. Cad í an chúis don difríocht seo?

Go minic, deirtear gurb é an teas a thugann Sruth naMurascaille leis i dtreo na hEorpa cúis na h-aeráide chineálta in Éirinn. Matthew Fontaine Maury a mhol an smaoineamh sin i 1855. Ach ní hé Sruth na Murascaille amháin gur cúis le seo. Is sruth aigéin é Sruth na Murascaile ar a glaotar ‘Sruth Teorann Iartharach’ de bharr a shuíomh in iarthar an Atlantaigh Thuaidh. Agus tá a leithéid de na sruthanna seo i ngach aigéan. San Aigéan Ciúin, is sruth teorann iartharach é an Kuroshio atá chomh láidir le Sruth na Murascaille. Ach, nuair a fhéachaimid ar na teochtaí dromchla i gcomparáid le meán-teocht an leithid (Fig. 2), seasann teochtaí arda aimhrialta an Atlantaigh amach. 

Eisceachtúlachas Atlantaigh

Glaotar Iompu Imsruthu an Aigéin ar an gcóras aigéin a bhogann an teas seo i dtreo iarthuaisceart na hEorpa. Is córas sruthanna aigéin é Iompú Imshruthú na Mara a bhogann uisce te ó thuaidh, i Sruth na Murascaille mar shampla. Tá an t-uisce seo te agus goirt. Agus an t-uisce seo ag cailliúint teasa de bharr próiseas éagsúla, cruthaíonn sé uisce fuar, domhain a fhilleann ó theas. Cruthaíonn an malartú den uisce fuar agus uisce te seo an iompar teasa is mó san aigéan. Scaoiltear an teas seo ón Atlantach agus iompaítear é i dtreo na hEorpa ag na príomhghaotha. ‘Sé meascán an aigéan agus an ghaoth cúis don aeráid chineálta eisceachtúil atá in iarthuaisceart na hEorpa.

Is tábhachtach é an meascán de ghaotha agus aigéan sa chomhrá faoi Eisceachtúlacht Atlantaigh. Ba éasca é féachaint ó Aillte an Mhóthair i rith an gheimhridh go dtí cósta fuaránta Labrador igCeanada  agus an difríocht 10 gcéim Celsius a chur i leith iompú an Atlantaigh. Ach is í cúis an difríocht teochta seo ná go bhfuil Labrador le cóir na gaoithe ó mhórchríoch fuaránta Cheanada, agus tá Éire le cóir na gaoithe ón aigéan. Is fearr an comparáid chun tionchar iompú an Atlantaigh ar an aeráid a léiriú, ná an comparáid idir Éire agus aeráid mhara den chineál céanna in iarthuaisceart an Aigéin Chiúin. Tá Baile Átha Cliatha 4C níos teo ná Seattle sa gheimhreadh agus is de bhuíoch iompú an Atlantaigh an difríocht seo. Cé nach bhfuil an comparáid seo chomh géar leis an gcósta Labrador, is ionann é difríocht 4C idir aeráid na hÉireann agus aeráid Portaingéil thuaidh.

Bagairtí i leith an Sruthú Iompaithe

Tá Iompú an Atlantaigh athruithe, le luaineacht mór san aeráid san oighearthréimhse deireanach ceangailte le titim agus athbheochan an sruthú iompaithe. Táthar ag tuar go dtiocfaidh meath ar an sruthú sa todhchaí – deir an Painéal Idir Rialtais don Athrú Aeráide go bhfuil an-seans go laghdóidh an Sruthú Iompaithe de 30% sa chéad atá amach romhainn. Má thagann an meath seo ar an sruthú, beidh tionchar ollmhór ar aeráid na hÉireann. Tá fianaise de seo ag méadú cheana féin. Tá teochtaí domhanda ag ardú ar bhonn leanúnach de bharr téamh domhanda antrapaigineach ach, san Atlantach Thuaidh, feictear spota fuar áit a bhfuil teocht íseal ag tarlú.

Ag ICARUS, táimid i mbun oibre chun tuiscint a fháil ar athruithe leanúnacha an Atlantaigh, chomh maith le tuiscint a fháil ar an tionchar atá ag sin ar Éirinn, ar iarthuaisceart na hEorpa agus ar áiteanna níos faide ó bhaile.