Unabated greenhouse gas emissions could lead to sea level rise twice as high as we had anticipated, according to a recent study published in Nature.
By the end of this century, scientists predict that sea levels could rise by over 2 meters on average. Note that this is a global average, meaning that some areas could see much higher local rises in sea level. For Small Island Developing States, this could mean the end of their existence altogether. The research has been welcomed by the scientific community, who had already raised reservations with regards to what was called “very conservative” estimates of sea level rise caused by a changing climate.
So what has changed, how could we suddenly double sea level rise? The answer lies in complex processes involved in the melting of ice in Antarctica. Previous estimates had failed to take into account accelerated melting caused by disintegrating ice sheets. In fact, scientists had only been able to consider the melting ice shelves due to increased air and water temperatures, and had ignored the impact of surface melt-water and rainfall which can help fracture large chunks of ice.
Climate change adaptation has been hailed as the ultimate recourse to prevent negative impacts of sea level rise. For instance, in a number of coastal regions, ecosystem-based adaptation helped by mangroves has been underway for some years already. Mangroves play a significant role in protecting coastal regions from intense storms including typhoons, expected to increase in frequency with climate change. Combined with sea level rise, such storm could be catastrophic, especially in densely populated areas.
In previous adaptation planning, the unique property of mangroves to “grow soil” had been counted on to mitigate the impacts of rising sea levels. The rate of growth of mangroves was very much in line with previous climate change projections, yet this new data would suggest that these fragile ecosystems would no longer be able to keep up with the increased rate of sea level rise. Hence, millions of the most vulnerable coastal communities will likely have to rethink their adaptation strategies, a very costly endeavour.
So what is the silver lining? If we achieve the targets set in the 2015 Paris Agreement, sea levels will continue to rise, but never to the rate which would occur if Antarctica’s melting was to start accelerating. Coastal communities will still need to adapt, but costs will be reduced and lives will be saved.
At least some increase in global temperatures over the next few decades is now generally accepted as inevitable. However due to the still not fully understood nature of our climate and the interplay between its complex feedback systems, models still do not agree on the magnitude of the changes expected on a regional scale. Therefore, policy makers have, more often than not, been avoiding the issue of addressing the climatic affects on future crop yields.
According to a United Nations report, in 2007 agriculture accounted for 45 per cent of the world’s labour force, or about 1.3 billion people. In low-income countries it was slightly higher at 55 per cent with the figure being closer to 66 per cent in many parts of Africa and Asia.
University of Leeds scientist Prof Andy Challinor and co-workers have been working on the issue of how farmers can adapt to a warming world. Case studies from Sri Lanka and Central America illustrate how a “no-regrets” adaptation approach can benefit farming communities regardless of the magnitude and timing of the warming itself.
The “no-regrets” approach to climate adaptation basically starts off by analysing the capacity of socio-economic groups such as communities, industries or countries. Adaptations strategies are then proposed that are both economically and politically feasible over a range of possible climate scenarios.
Sri Lanka is a country heavily dependent on agriculture. Current climate model predictions for changes in annual precipitation vary in magnitude and even direction of change, i.e some predict increases in rainfall while others predict a drop for a range of emission scenarios.
Given such uncertain predictions the government of Sri Lanka took a pragmatic approach to climate adaptation. It took into account the current capacity of local farmers to implement cost effective, low risk responses to high vulnerability districts.
Strategies implemented include the restoration of ancient water storage tank systems to harvest rainwater during the wet season to be used later in the dry season, the development of sustainable groundwater usage, adoption of micro-irrigation technologies and waste water reuse. These “no-regrets” changes enable a more sustainable approach to farming for Sri Lanka’s farming communities.
In Nicaragua 14% of the gross domestic product comes from coffee exports. While coffea arabica is the main source of livelihood for many farmers it is a crop very sensitive to climatic conditions. It requires stable temperatures between 19-22 degrees Celsius and little variation in annual rainfall. This translates into only certain altitude bands being suitable for arabica plantations. In Nicaragua this band lies between 400-1400m above sea level while in Columbia it is 1200-1800m.
Most climate models for this region predict a temperature rise over the next few decades but the models do not agree on the magnitude of the increase. For example, a temperature increase of 2 degrees Celcius (one of the more optimistic estimates) would result in a 400m change in the elevation range of the crop, equivalent to a loss of two thirds of the current altitude range.
The “no-regrets” adaptation plan for this region involves a change to a different crop, one more favourable to increased temperatures. At lower elevations arabica can be replaced with cocoa which has a similar cash value and is better suited to the higher temperature conditions. At higher altitudes in regions newly becoming suitable to coffee plantations the environmental impacts of the crop is considered to be too harmful. The region in between must involve a dynamic approach where farmers respond to the changing climate by adjusting their agricultural practices. Incremental adaptations through greater shading and other management practices including diversification will be the appropriate response.
Feeding the future
Despite uncertainties in regional climate forecasts much progress can be made by focusing on what we do know. By assessing the current capacity of local governments and farmers simple adaptation strategies can be implemented that are flexible over a range of probable climate futures. It is clear that as our climate continues to warm the affects on agriculture will become increasingly visible. We must start embracing changes to our agricultural practices and adaptation strategies. With a world even now, under food shortages we cannot afford to remain indifferent.
“Climate projections will always have a degree of uncertainty, but we need to stop using uncertainty as a rationale for inaction,” says Dr Sonja Vermeulen, head of research at Climate Change, Agriculture and Food Security (CCAFS).