Improved projections of the contribution of glaciers and ice sheets to sea level will be provided to the 2013 IPCC report and European policymakers, providing them with the best basis for coastal defence planning.ice2sea Programme Coordinator David Vaughan, of the British Antarctic Survey, sheds light on how scientists are exploring the role of glaciers and ice sheets in sea level rise...
Professor David Vaughan
Ensuring the future security and prosperity of our growing coastal cities and survival of many unique coastal habitats requires scientists to deliver reliable sea level projections upon which adaptation, management and protection plans can be based.
Around 10 million people each year are affected by coastal flooding. According to a study by the UK Met Office, as populations migrate towards coastal regions, this number will increase to 30 million by 2080, with the potential for an even higher figure if sea level rise is at the upper end of the range of projections. Global sea level rise
Since the early 1990s, scientists have used satellites to measure global sea level rise with great precision – on average it has been around 3mm every year. However, evidence suggests that this rate has risen in recent decades, and by the end of this century a total sea level rise of around 1m is possible (compared to levels recorded in 1990).
Currently, sea level rise results from several different climate-driven processes: thermal expansion of the oceans (~1mm per year), the melting of mountain glaciers around the world (~1mm per year), and retreat of the world's polar ice sheets (0.7mm per year). Thermal expansion and melting mountain glaciers can be predicted with confidence; the greatest remaining uncertainty lies in the contribution of ice loss from the polar ice sheets resting on Antarctica and Greenland. ice2sea science for policy
The 2007 Intergovernmental Panel on Climate Change (IPCC) report highlighted ice sheets as the most significant remaining uncertainty in projections of sea level rise. In particular, understanding of the crucial ice sheet effects was 'too limited to assess their likelihood or provide a best estimate of an upper bound for sea level rise'. Several substantial science programmes now aim to address this significant question.
The ice2sea programme's main objective is to build a scientific foundation for policy development surrounding sea level rise. Improved projections of the contribution of glaciers and ice sheets to sea level will be provided to the 2013 IPCC report and European policymakers, providing them with the best basis for coastal defence planning. Understanding global sea level
This collaboration draws together the EU's scientific and operational expertise in order to better understand sea level rise and the uncertainty surrounding it. Using past records, observational measurements and computer modelling techniques, ice2sea scientists are:
•Measuring current rate changes in glaciers and the polar ice sheets;
•Understanding the processes by which glaciers and ice sheets are affected by atmospheric and ocean change;
•Developing new projections of sea level rise for European coasts over the next 100-200 years.
In Greenland, ice2sea scientists have drilled to the bottom of the ice sheet, to measure how meltwater produced on warm summer days finds its way to the bed of the ice sheet, where it lubricates the bed and allows ice to flow faster. This data is crucial in predicting the behaviour of the ice sheet in a warming climate, when summer melting will increase.
Results from this and other field campaigns are delivered to different groups within ice2sea, most notably to the computer modelling teams responsible for building a new generation of more complete and precise methods of projecting the contribution of ice to sea level rise. This work begins with projections of global climate based on different emissions of greenhouse gases. These global climate models are then used to drive regional atmospheric models that allow projections of the direct specific atmospheric changes likely to occur in Greenland and Antarctica, and ocean models that predict how oceans deliver heat to the ice sheets. Several new ice sheet models are in development, and these will be driven using the atmosphere and ocean model output, to predict the changes in the ice sheets.
Additionally, ice2sea has built a new inventory of the world's 100,000 mountain glaciers, and can therefore use its global climate projections - and a statistical model of glacier change - to make similar projections for glaciers.
Finally, the projections of ice loss from the ice sheets and glaciers around the world will be fed into one more model. This model will tell us how the melting ice will be distributed around the world's oceans and seas, and thus how global sea level change will be felt on specific coastlines, with a particular focus on Europe. Results
Sea level projections are expected from ice2sea in July 2012, in time to feed into the next report of the IPCC, but early results are already being delivered. There is increasing evidence that the loss of ice from polar ice sheets is caused not by warming air, but by the warming waters produced as ocean circulation patterns begin to change. Projections of ocean change in the fjords around Greenland and the frigid seas around Antarctica show that this is likely to continue in the future.
The ice2sea programme is an ambitious one, but its results will be of real value to engineers and planners across Europe. The sea level projections it will produce will provide a sound basis for risk management in coastal cities and habitats. It is a good example of what can be achieved by funding scientific collaboration across national boundaries, but the programme will also leave another legacy – in training a new generation of early-career researchers who will be capable of taking the work forward in future, further reducing the uncertainties surrounding sea level rise, and the risks to our coasts.This article first appeared on publicservice.co.uk: Rising to the challenge.