May 2011

We are the first generation facing the evidence of global change. It therefore falls upon us to change our relationship with the planet, in order to tip the scales towards a sustainable world for future generations. 

The 3rd Nobel Laureate Symposium on Global Sustainability
– Transforming the World in an Era of Global Change, was held May 16-19, 2011 in Stockholm, Sweden.  This was a small (~50) gathering of some of the world’s most renowned thinkers and experts on global sustainability and included numerous nobel laureates from many disciplines.  They have produced a memorandum, shown here being signed by Nobel Laureate Paul Crutzen.

The Stockholm memorandum can be downloaded here, but here is a sample:

The Earth system is complex. There are many aspects that we do not yet understand. However, we are the first generation with the insight of the new global risks facing humanity. We face the evidence that our progress as the dominant species has come at a very high price.

Unsustainable patterns of production, consumption, and population growth are challenging the resilience of the planet to support human activity. At the same time, inequalities between and within societies remain high, leaving behind billions with unmet basic human needs and disproportionate vulnerability to global environmental change.

This situation concerns us deeply. As members of the Symposium we call upon all leaders of the 21st century to exercise a collective responsibility of planetary stewardship. This means laying the foundation for a sustainable and equitable global civilization in which the entire Earth community is secure and prosperous.

Science makes clear that we are transgressing planetary boundaries that have kept civilization safe for the past 10,000 years. Evidence is growing that human pressures are starting to overwhelm the Earth’s buffering capacity.

Humans are now the most significant driver of global change, propelling the planet into a new geological epoch, the Anthropocene. We can no longer exclude the possibility that our collective actions will trigger tipping points, risking abrupt and irreversible consequences for human communities and ecological systems.

We cannot continue on our current path. The time for procrastination is over. We cannot afford the luxury of denial. We must respond rationally, equipped with scientific evidence.

Our predicament can only be redressed by reconnecting human development and global sustainability, moving away from the false dichotomy that places them in opposition.

In an interconnected and constrained world, in which we have a symbiotic relationship with the planet, environmental sustainability is a precondition for poverty eradication, economic development, and social justice.

Our call is for fundamental transformation and innovation in all spheres and at all scales in order to stop and reverse global environmental change and move toward fair and lasting prosperity for present and future generations.


Recent increases in ice discharge from marine outlet glaciers in Greenland (e.g., [1], [2]) have been associated with ice-ocean interactions (e.g., [3], [4], [5]). Warming of subsurface waters in contact with the submarine bases of these glaciers result in additional melting of the ice and changes to the stress balance of the ice flow.

Here’s a short video from WHOI physical oceanographer Fiamma Straneo explaining the connection between ocean conditions and climate-driven changes to Greenland glaciers (she also describes some of the challenges in conducting scientific research in the far north).

Currently, numerical ice-dynamic models are not suitably equipped to capture these interactions and therefore this hampers our ability to predict Greenland’s contribution to sea level rise.  Part of my research aim is to work towards improving ice-flow models so that they better represent these processes.


[1] Joughin, I., Abdalati, W., Fahenstock, M., 2004. Large fluctuations in speed on Greenland’s Jakobshavn Isbrae Glacier. Nature 432, 608-610.

[2] Rignot, E., Kanagaratnam, P., 2006. Changes in the velocity structure of the Greenland Ice Sheet. Science 311, 986–990.

[3] Holland, D. M., Thomas, R. H., Young, B. D., Ribergaard, M. H., 2008. Acceleration of Jakobshavn Isbrae triggered by warm subsurface ocean waters. Nat. Geosci. 1, 659–664.

[4] Straneo, F., Hamilton, G. S., Sutherland, D. S., Stearns, L. A., Davidson, F., Hammill, M. O., Stenson, G. B., Rosing-Asvid, A., 2010. Rapid circulation of warm subtropical waters in a major glacial fjord in East Greenland. Nat. Geosci. 3, 182-186.

[5] Rignot, E., Koppes, M., Velicogna, I., 2010. Rapid submarine melting of the calving faces of West Greenland glaciers. Nat. Geosci. 3, 187-191.

A working group commissioned by The Pontifical Academy of Sciences [website & wikipedia entry] “to contemplate the observed retreat of the mountain glaciers, its causes and consequences” has released a report entitled Fate of Mountain Glaciers in the Anthropocene.  The groups consensus statement is a warming to all humanity and a call for fast action.  This is their declaration:

“We call on all people and nations to recognise the serious and potentially irreversible impacts of global warming caused by the anthropogenic emissions of greenhouse gases and other pollutants, and by changes in forests, wetlands, grasslands, and other land uses. We appeal to all nations to develop and implement, without delay, effective and fair policies to reduce the causes and impacts of climate change on communities and ecosystems, including mountain glaciers and their watersheds, aware that we all live in the same home. By acting now, in the spirit of common but differentiated responsibility, we accept our duty to one another and to the stewardship of a planet blessed with the gift of life.

We are committed to ensuring that all inhabitants of this planet receive their daily bread, fresh air to breathe and clean water to drink as we are aware that, if we want justice and peace, we must protect the habitat that sustains us. The believers among us ask God to grant us this wish. “

A pdf of the complete statement can be accessed here.  The authors recommend pursuit of three measures:

  • immediate reduction of worldwide carbon dioxide emissions,
  • reduction of concentrations of warming air pollutants such as soot, ozone, methane and hydroflurocarbons by up to 50 percent, and
  • preparation to adapt to climate changes that society will not be able to mitigate.

Is the United Nations goal of limiting global warming now out of reach?  2°C warming is the globally agreed target set to avoid dangerous climate change reiterated at the 2009 UN Copenhagen Accord.  This is now nearly impossible according to a recent study by researchers from British Columbia, Canada [1] (see also this paper [2]).

“The paper finds that reaching that goal would require that greenhouse emissions “ramp down to zero immediately” and that scientists deploy means, starting in 2050, to actively remove greenhouse gases from the atmosphere. Previous modeling ([3], [4]) efforts have already highlighted the difficulty of reaching the 2˚C goal.”  Science Now

[1] V. K. Arora et al., Carbon emission limits required to satisfy future representative concentration pathways of greenhouse gases, Geophys. Res. Lett., 38, L05805, doi:10.1029/2010GL046270, 2011.

[2] K. Anderson and A. Bows, Beyond ‘dangerous’ climate change: emission scenarios for a new world, Phil. Trans. R. Soc. A, 369, 20-44, doi:10.1098/rata.2010.0290, 2011.

[3] M. Meinshausen et al., Greenhouse-gas emission targets for limiting global warming to 2°C, Nature, 458, doi:10.1038/nature08017, 2009.

[4] M. R. Allen et al., Warming caused by cumulative carbon emissions towards the trillionth tonne, Nature, 458, doi:10.1038/nature08019, 2009.

Some suggest a global 2 degree Celsius limit is rather arbitrary and policy makers should instead focus on regional impacts and legislate to prevent so-called tipping points.  See this opinion piece by Tim Lenton in Nature.  This idea is a good future aspiration, although not sensible for present as we do not know well enough regional impacts or when potential tipping point might be reached; furthermore, a global rise in temperature of two degree Celsius will almost certainly already mean some serious regional impacts for some parts of the planet.  Tim does suggest that the United Nations Framework Convention on Climate Change (UNFCCC) be extended to limit the rate and gradients of climate change and this indeed could be a helpful starter.

Wally Broecker, an outstanding American scientist and pioneer of Earth System Science, in a book (fixing climate) published in 2009 suggested, somewhat controversy, that we implement large-scale carbon dioxide removal from the atmosphere.  I like his reasoning – in the past we dumped our sewage in the streets, until we learnt about the spread of disease and the importance of hygiene, so the Victorians built a sewage network to dispose of the waste.  Likewise, we are dumping carbon dioxide, a waste byproduct of burning fossil fuels, into the atmosphere.  We now realise that this is leading to climate change with potential devastating consequences.  We therefore need to employ an extensive network of machines to scrub carbon from the atmosphere and pump it into deep geologic permanent storage.    However, the trouble is that this technology has not been tested at industrial scale, will cost a fortunate, will need massive widespread implementation, and the feasibility and capacity of storage sites is dubious.

The bottom line – we must aggressively cut all our greenhouse gas emissions and the sooner we start the better chance we have of limiting dangerous climate change.