Copenhagen: A new global deal for sustainable development?
There are nine planetary boundaries that should be respected in order to reduce risking the self-regulating capacity of the planet. The environmental conference is only a first step.
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But when it comes to climate change, our research shows that focusing on reducing emissions without putting in place mechanisms to maintain the integrity of current "carbon sinks" in oceans and on land will prevent us from making any significant gains in greenhouse-gas reductions.Skip to next paragraph
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This is because, to date, nature has been doing us a huge favor.
Land and oceans have been providing a free ecosystem service, in the form of sinks that store carbon dioxide. As much as 50 percent of today's carbon dioxide emissions are absorbed by terrestrial and marine ecosystems.
But the capacity of this ecosystem service may now be decreasing due to temperature increases, acidification of oceans, and land-use changes.
And if we continue to warm and acidify the oceans and cut down forests, we risk not only collapsing ecosystems followed by increased human starvation, but also reducing or even reversing this free service nature provides us . If the planet turns from friend to foe, i.e., from sink to source, when eroding the resilience of the biosphere, we will enter a potentially disastrous domain of runaway climate change. To avoid such outcomes will require radical action not only on emission reductions but also on active stewardship of the world's ecosystems.
The boundaries are, in other words, tightly coupled; transgressing the boundaries for nitrogen, land, water, oceans, ozone, and biodiversity will all threaten the ability to stay within the safe space of the climate system. An example of this is that fresh water determines the amount of biomass growth, i.e., the amount of carbon captured from the atmosphere in trees and plants, which in turn determines the amount of organic matter, i.e., carbon, in the world's soils. The world's soils hold some 1,500 billion tons of carbon, compared with the annual global emissions of some 9 billion tons of carbon.
Whether or not humanity will be able to stabilize climate within safe levels depends upon our ability to reduce emissions and constructively manage a number of critical natural systems on the planet.
This profoundly changes the agenda on solving the problem of anthropogenic climate change, as it indicates the need for an Earth systems approach to climate mitigation.
This is a rather depressing conclusion given the worrying state of the current climate negotiations, where the rift continues to widen between what science shows is needed to solve the human-induced climate problem and what is considered politically possible to do.
But if the best available science is telling us that the Earth system is in serious jeopardy of tipping into an unfavorable state for human development, should today's political realities dictate how we define success?
Unfortunately, in this drama there are no second chances. Nature does not do bailouts.
This is why reaching a substantive global agreement in Copenhagen on reducing greenhouse-gas emissions is necessary, but not sufficient for steering clear of catastrophic, irreversible tipping points in the Earth system.
To reduce the risk of tipping into the unknown, we need a new global deal for sustainable development.
Copenhagen should be viewed as a first, necessary step toward this new deal.
Johan Rockström is the director of the Stockholm Resilience Centre at Stockholm University, and lead author, joined by Nobel laureate Paul Crutzen and others, of a new article in the scientific journal Nature on how to cope with climate change.