The Niger Basin could cross the 2˚C threshold in the next 25 years
Climate and disaster risks
The international ambition to limit global warming to 2°C relative to pre-industrial levels was re-affirmed and included in the COP21 Paris agreement in January this year. But, when will we hit 2˚C and what will it mean for vulnerable regions such as the Maldives, Bangladesh and West Africa?
Projections of future change in the Niger Basin under 2°C
A study conducted by Impact2C shows a stronger warming signal in the Southern Sahara than the global mean, with the 2°C threshold being exceeded before 2050 under a stabilisation scenario, and in the next 25-30 years under a high emission scenario. There is a projected small increase in annual precipitation with increasing rain intensity and a decreasing number of rain days. In many regions, there are also indications of changes in the onset and cessation of rainy seasons. Large parts of the Niger Basin contain flood-pulse dependent ecosystems, on which livelihoods depend. However, the Niger Basin has also experienced extensive hazardous flooding over the past two decades with millions of people affected. While there are some regional differences in magnitude, for most parts of the Niger Basin, the analysis found that hazardous floods are expected to increase, though the uncertainty range is large.
Similar analysis was undertaken for droughts. The potential impact of such events is high, as the national economies in these countries are largely agricultural based and production is mainly rain-fed (and flood recession-fed) and thus highly climate sensitive. The hydrological cycle also affects other natural resources – in the Inner Niger Delta in Mali, for example, fish yields are directly related to the extent of the delta inundated during flooding. Results indicated a much greater variation in outcomes, depending on the projection and location. For some areas in the Niger Basin, notably the central Benue valley, the southern Bani basin and parts of the Guinea highlands, there were consistent trends of longer periods of low flows and more severe hydrological droughts.
Importantly, many of the projected changes will increase existing risks. A key priority is to build adaptation to better cope with climate variability – now and for the future. However, a strong finding is that this adaptation needs to take place in an integrated manner, considering disaster risk reduction, poverty eradication and economic growth and development simultaneously.
Mainstream and integrate
This can be best advanced by mainstreaming climate change adaptation into existing development policies and planning. Stakeholders in the basin stressed the need for reliable weather forecasts and projections, early warning systems and supporting structures and networks. A key component of mainstreaming is the need to fully implement and conduct integrated water resources management (IWRM) in order to balance water resources demands across multiple end-users, including biodiversity and ecosystem services, and to help address water-induced disasters and shocks.
Political discussions on the European goal to limit global warming to 2˚C need to be informed by the best available science on projected impacts and possible benefits. IMPACT2C enhances knowledge by providing information on the potential impacts of 2˚C of global warming. It also considers the economic costs of these impacts, as well as potential responses. The project uses a range of models within a multi-disciplinary international expert team and assesses effects on water, energy, infrastructure, coasts, tourism, forestry, agriculture, ecosystem services, and health and air quality-climate interactions.
For more information about the project visit: impact2c.hzg.de
Reference to additional information can be found in the IMPACT2C Policy Briefing.
The Swedish Meteorological and Hydrological Institute’s (SMHI) HypeWeb Niger-HYPE is an interactive map that allows users to explore the potential effects of climate change on floods, droughts and other water-related phenomena in the Inner Niger Delta. This tool is intended for use in creating adaptation strategies in West Africa.
This article originally appeared in the Climate Services Partnership January 2016 newsletter.