by Stuart Cunningham, July 2014. R/V Knorr, mid-Atlantic.
“I’m truly sorry man’s dominion
Has broken Nature’s social union,
An’ justifies that ill opinion
Which makes thee startle
At me, thy poor, earth born companion
An’ fellow mortal!” – Robert Burns, 1785.
Burns writes of our interfering with the balance of nature – inadvertent or otherwise – and our short-lived sharing of the earth’s environment: in this Poem writing about the panic of a mouse and her brood with the turning of her nest by the plough’s harrow. Settled opinion is that anthropogenic forcing is the dominant mechanism driving long-term climate change: controversies now are more about our reaction to this. Long-term in this context means that over a few decades we can see the slower man-forced changes hidden amongst larger, naturally occurring climate variation. We need now to focus on the regional impacts of global warming: measuring shorter term changes so that the long term trends can be quantified. Will my home region be warmer or drier or submerged by sea-level rise? Global average change hides the nature of much larger regional changes. Observing the ocean gives us a Plimsoll line for future change, and the stimulus for better theories of oceans and the climate.
So why are we at sea?
The atmosphere and ocean transport heat from the equatorial regions to higher latitudes: this energy transfer is our climate. The atmosphere reacts quickly, while the ocean controls slower and long-term energy transports relating to our long-term climate variations. Warming and increased precipitation at high latitudes caused by global warming means that the heat transported by the Atlantic is likely to reduce over the coming century: this has long-term implications for climate patterns (particularly in the North Atlantic where the ocean acts as a “fan assisted storage heater for Europe”(1). Beginning in 2004 a purposefully designed transatlantic monitoring array began measuring the Atlantic circulation between Morocco and Miami (2). Observing the ocean is a very buy propecia online hard and expensive technical problem. Controversial in its infancy, RAPID-MOCHA blazed a trail for oceanographers: showing how by thinking big, and with cooperation between teams of brilliant scientists and with the long-term commitment of funding agencies, oceanography and climate science can tackle one of the leading climate problems in the 21st century: what controls Atlantic ocean heat transport? how is changing now: how is it likely to change in the future?; and with the ambition to forecast climate out to decadal timescales.
RAPID-MOCHA nailed the problem in the subtropical Atlantic, and so was born the ambition to install a similar purposefully designed observing system in the subpolar North Atlantic. In the subtropics we measure the maximum heat transport by the ocean. This diminishes greatly by the subpolar region: the heat lost to the atmosphere being central to climate variability for countries around the Atlantic (affecting hurricane variability, Sahel drought, Amazonian rainfall, extreme European winters, fish stock distributions). Thus OSNAP (a child of RAPID), with moorings from Newfoundland to Greenland to Scotland, aims to measure the heat transport in the subpolar region. Combining with RAPID we measure the critical Atlantic heat transport throughout the North Atlantic and the exchanges with the atmosphere. OSNAP is another milestone in our goal of building an integrated Atlantic observing network.
Man’s dominion over Nature, we now understand, is illusory. King Knut the Great 1200 years ago understood (and quite possibly demonstrated?) the futility of believing otherwise. But we can observe, theorise and understand our climate: more, better, better planned and long-term observations are the way we will make progress in understanding. Otherwise we will be unprepared for change now and for future generations. Observing the oceans is difficult but it must be done; and it will be done. This research expedition is our contribution.
1 Ellett, D. J. The north-east Atlantic: A fan-assisted storage heater? Weather 48, 118-126, doi:papers2://publication/doi/10.1002/j.1477-8696.1993.tb05861.x (1993).