What will be the contribution to sea level rise of the ice sheets in Greenland and Antarctica over the coming century?

Sea level change is one the most outstanding issue in Earth System Science in terms of scientific and societal impact. The largest uncertainty in sea level projections is the rate of melting of ice sheets into the ocean in a warming climate. We are far from being able to make predictions of ice sheet evolution. Progress is urgently needed.

Is Global Change such a bad thing after all?

Allow me to play Devil’s advocate for a moment in order to make rather cynical observations that – unfortunately – common-sense is dictating me: (1) melting of the arctic ice cap offers fantastic opportunities for transport, land use and oil extraction; (2)sea level rise will offer Pacific islanders opportunities (denied to them up until now) of relocation in often far better places, due to international pressure; (3) as some places will probably suffer extreme weather patterns due to Climate Change, other will enjoy far better conditions compared with historical records; (4) oilpalm plantations are indeed prime destroyers of biodiversity but they sustain far more people per acreage compared with native forests…and might play an essential role in solving the energy dilemma in many tropical countries.

I guess this is enough to illustrate my point: ‘average Joe’ has always had the feeling that WE, human beings, are integral parts of an endless journey on a boat called GAIA. Over billions of years, things have changed, they are currently changing and will most certainly continue to do so in the future. Sometimes changes are brutal and their consequences dramatic for entire civilizations.

Here is the crux of my argument: earth sciences (and, by definition, earth scientists) need to embark into a history-contingent and holistic story-telling of the changes we observe. Over the last century, earth sciences have moved towards causality-driven approaches and models, renegating – to some extend – basic premises of physics where things are, evolve and interact without searching for causal factors as such.

This is a paramount shift for earth sciences and the way we communicate its results: as long as ‘average Joe’ will feel like he belongs to the group of culprits who CAUSE all these changes…nothing will change as a well established psychological process, called cognitive dissonance, will prevent humanity at large to become pro-active about Global Change. Science needs to step out from the ‘blame game’ as soon as possible and to go back to Newton’s fundamentals: things and beings are, evolve and interact.

If the current perturbations we call Global Change serve as a wake-up call, I’d say that it is not such a bad thing after all!

How will polar climate respond to continued global warming?

Current climate models do not adequately simulate the behaviour of the climate at the poles (a) because they are based largely on tropical to mid-latitude processes, and (b) because they ignore the effects of changing ozone through time. Without improvements in polar climate models we shall be unable to provide any adequate projection of the decay of ice sheets and their contribution to sea level rise.

What will be the true magnitude of cumulative effects of global change?

To date many global change questions have focused on a component (e.g. the C cycle or sea level rise). The true outcomes of global change will be dictated by cumulative impacts, interactions and feedbacks. If they’re not addressed we may get some nasty non-linear surprises.