The Water-Energy-Land (WEL) nexus and the analysis of Land issues - - PowerPoint PPT Presentation

The Water-Energy-Land (WEL) nexus and the analysis of Land issues

Karl Harmsen Sr Fellow, ZEF, University of Bonn Consultant, DIE, Bonn European Report on Development (ERD) 2012 Consultation on Governance of Natural Resources with a focus on Land NH Hotel, Maastricht, 18-19 May 2011

• 1. WEL nexus:

definition

energy water land

NEXUS

• 1. a connection
• r link
• 2. a connected

group or series

• 2. WEL nexus:

= Water = Energy = Land

2.1. Water

• Hydrological cycle
• Land/water – atmosphere

interactions

• Water quality
• Soil water balance and water-use

efficiencies

• Soil & water conservation
• Water harvesting & small reservoirs

West African Science Service Center on Climate and Adapted Land Use

< 1% liquid water

Precipitation Evapo- Transpiration Soil Storage Groundwater Recharge Surface Water Recharge

[Harmsen, 2007]

vegetation

Function of Temperature

2.2. Energy

• Global energy balance
• land use/land cover (albedo)
• greenhouse gases,
• aerosols, dust, bush fires,

wind erosion

• evapo-transpiration
• Use of fossil and renewable energy
• Production of sources of renewable

energy

78% 55%

Energy balance The difference between the total incoming and total

• utgoing energy in the climate system. If this balance

is positive, warming occurs; if it is negative, cooling

• ccurs. Averaged over the globe and over long time

periods, this balance must be zero. Because the climate system derives virtually all its energy from the Sun, zero balance implies that, globally, the amount of incoming solar radiation on average must be equal to the sum of the outgoing reflected solar radiation and the outgoing thermal infrared radiation emitted by the climate system. A perturbation of this global radiation balance, be it anthropogenic or natural, is called radiative forcing.

Global average radiative forcing (RF) in 2005 (best estimates and 5 to 95% uncertainty ranges) with respect to 1750 for CO2, CH4, N2O and other important agents and mechanisms, together with the typical geographical extent (spatial scale) of the forcing and the assessed level of scientific understanding (LOSU). Source: IPCC, 2007.

Comparison of observed changes in surface temperature with results simulated by climate models using either natural or both natural and anthropogenic forcings. Decadal averages of observations are shown for the period 1906-2005 (black line) plotted against the centre of the decade and relative to the corresponding average for the 1901-1950. Lines are dashed where spatial coverage is less than 50%. Blue shaded bands show the 5 to 95% range for 19 simulations from five climate models using only the natural forcings due to solar activity and volcanoes. Red shaded bands show the 5 to 95% range for 58 simulations from 14 climate models using both natural and anthropogenic forcings (IPCC, 2007)

Relative changes in precipitation (in percent) for the period 2090-2099, relative to 1980-1999. Values are multi-model averages based on the SRES A1B scenario for December to February (left) and June to August (right). White areas are where less than 66%

• f the models agree in the sign of the change and

stippled areas are where more than 90% of the models agree in the sign of the change (IPCC, 2007)

AFRICA December to February

AFRICA June to August

interactions and links:

• 1. Land & water (the surface of the Earth) play a

role in the energy balance [climate change]

• 2. Interventions at the surface of the Earth may

use energy, both renewable and fossil (e.g., solar energy for photosynthesis cq crop growth, fossil fuel for transport and machinery)

• 3. Interventions at the surface of the Earth may

generate sources of renewable energy (e.g., food and feed, fuelwood, organic waste, oil crops)

2.3. Land Land productivity & degradation

• loss of vegetation
• water & wind erosion
• deterioration of the physical,

chemical & biological soil quality

• soil & water conservation
• carbon and nitrogen cycles

Degraded soils. Soil degradation is a key global environmen- tal indicator. Very degraded soils are found especially in semi-arid areas (Sub-Saharan Africa, Chile), areas with high population pressure (China, Mexico, India) and regions undergoing deforestation (Indonesia). Degraded soils reduce the possibilities for agriculture, increasing the expansion of drylands/deserts and hightening the risk for

• erosion. This map presents the state of

global soil degradation, from the GLASOD study in 1997 (UNEP-GRID Arendal website)

Deforestation in Cote d’Ivoire (source: UNEP-GRID)

Carbon cycle:

• Emission of CO2 and/or CH4
• Mineralization-immobilization

(sequestration) of carbon = source of energy for biota = important for soil quality = availability of trace elements to plants

Nitrogen cycle:

• Mineralization-

immobilization

• Nitrate reduction
• Emission of NOx

• 3. Land Use

Systems

Reference: LADA, 2008. Mapping land use systems at global and regional scales for land degradation assessment analysis. Nachtergaele, F., and Petri, M. LADA Technical Report no. 8, version 1.1.

The Land Use Database of the World was developed a part of the project Land Degradation Assessment in Drylands (LADA), a 4-year project funded by the Global Environment Facility (GEF). The project is implemented by the United Nations Environment Programme (UNEP) and executed by the Food and Agriculture Organization

• f the United Nations (FAO).

Farming systems in West Africa:1, irrigated; 2, tree crop; 7, root crop; 8, cereal-root crop mixed; 11, agro-pastoral millet/sorghum; 12, pastoral; 13, sparse (arid); 14, coastal artisanal fishing (From FAO).

environment

system

Conservation of mass (k): Influx – Efflux = Accum/Deplet – Source/Sink If source/sink = 0  Influx - Efflux = Accum/Deplet Thus, if Influx = Efflux  Accum/Deplet = 0 That is, there is no accumulation or depletion

• f mass (k)

System is sustainable if Influx = Efflux Or if Accum or Deplet are ‘sustainable’

Solar energy

H2O CO2 O2

Photosynthesis - Respiration Leaching

Natural Forest

Solar energy

H2O CO2 O2

Photosynthesis - Respiration Leaching

Field crops

Biomass: CHONSP + minerals Fertilizer minerals

environment

mass energy system

Iagric output

agric inputs labour machinery rural credit knowledge livestock pests diseases

• 4. Scales in space

and time

space time processes upscaling & downscaling

Spatial scales

< 1 km - plot 1-10 km - local 10-100 km - meso 100-1000 km - regional >1000 km - global

T = 5 years

T = 10 years

• 5. Derive criteria for

integrated NRM

CONTEXT Effective natural resource management (NRM) for inclusive and sustainable growth in the context of increased scarcity and climate change: What roles for the public and private sectors? KEY WORDS

• integrated NRM
• sustainable development
• increasing scarcity of resources
• climate change

Energy balance:

• 1. decrease the emission of greenhouse gases

(e.g., CO2) and reduce activities that negatively affect the energy balance (increase in ∆H) such as wind erosion (dust), burning of vegetation (aerosols, CO2), land degradation (loss of vegetation, decrease in productivity, soil color=albedo) Criteria for NRM for sustainable development against the background of increasing scarcity of the resources and climate change

• 2. Fossil energy: decrease the use of fossil energy
• r replace by renewable energy
• 3. Develop new sources or technologies of

renewable energy, promote their use and increase the efficiency of these products. Water:

• 4. Decrease negative human interference with

the water cycle

• 5. Limit the use of fossil groundwater and

develop alternatives. Criteria (continued)

• 6. Increase the efficiency of the use of sweet

water for agricultural, industrial and domestic

• purposes. In agriculture, increase water use

efficiency by plants and animals, and decrease losses from the land (evapo-transpiration, leaching, surface runoff) and from water distribution (irrigation) systems .

• 7. Protect the quality of surface and

groundwater. Criteria (continued)

Land:

• 8. Make efficient use of the resource (scarcity!)

and decrease degradation of the resource, e.g., loss of vegetation and biodiversity, water and wind erosion, loss of soil organic matter, deterioration of physical and chemical soil properties, etc.

• 9. Optimize land management with regard to the

water cycle (including quality!) 10 Reduce the emission of greenhouse gases (C- cycle, N-cycle, S-Cycle), aerosols, dust (fires) Criteria (continued)

• 6. Optimize the

functioning of the system in terms of WEL and derive management strategies

LEISA: Low external input sustainable agriculture

Fertilizer Use in 2005-07 in the Netherlands 892.4 kg/ha, Niger 0.4 kg/ha and Mali 0.0 kg/ha

Most agriculture in Africa (other than the RSA) is LEISA by definition, as little or no external inputs are used. In W Europe LEISA usually means less external inputs than are currently used. In SSA LEISA may well mean more external inputs than are currently used, although in some cases the inputs and the associated technologies may be different. E.g., zero or reduced tillage practices, use of organic residues, mulching for moisture conservation, etc.

It should thus be emphasized that “low-input” does not mean “zero-input”. Experience with the SubSahara Africa Challenge Programme (SSA-CP) has shown that, use of organic residues , low or zero tillage and mulching for moisture conservation, alongside the use

• f small quantities of mineral fertilizers and the use

improved maize varieties (disease resistance) can make a difference and break the poverty trap. In addition to access to agricultural extension, rural credit and input and output markets, this requires the

• rganization of farmers in “Innovation platforms”,

which provides an alternative for the traditional “linear approach” to agricultural extension.

int agric res nat agric res nat ext serv farmer input market

• utput

market local govt rural credit

Linear TT approach

int agric res nat agric res nat ext serv farmer input market

• utput

market local govt rural credit

Innovation platform TT approach

• 6. Conclusion

The WEL nexus can provide a framework for the analysis of Land issues, based on an under- standing of the roles of water, energy and land, and their links and interactions in well-defined land-use systems, clearly related to x and t scales. Criteria for analysis and development of governance and management strategies would not be very different from those derived from the Millennium Ecosystem Assessment. Poor countries in SSA would need the assistance of Europe to implement sustainable development policies and management strategies.

West African Science Service Center on Climate and Adapted Land Use

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