10 research outputs found
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Current fire regimes, impacts and the likely changes – IV: tropical Southeast Asia
The Southeast Asian region is experiencing some of the world’s highest rates of deforestation and forest degradation, the principle drivers of which are agricultural expansion and wood extraction in combination with an increased incidence of fire. Recent changes in fire regimes in Southeast Asia are indicative of increased human-causd forest disturbance, but El Niño–Southern Oscillation (ENSO) events also play a role in exacerbating fire occurrence and severity. Fires are now occurring on a much more extensive scale - in part because forest margins are at greater risk of fire as a result of disturbance through logging activities, but also as a result of rapid, large-scale forest clearance for the establish-ment of plantations. Millions of hectares have been deforested and drained to make way for oil palm and pulpwood trees, and many plantation companies, particularly in Indonesia, have employed fire as a cheap land clearance tool; uncontrolled fires have entered adjacent forests or plantation estates, and burnt both the forest biomass and, in peatland areas, underlying peat. Forest fires cause changes to forest structure, biodiversity, soil and hydrology. Repeated fires over successive or every few years lead to a progressive decline in the number of primary forest species. Fire leads to reduction in both aboveground and below ground organic carbon stocks and also changes carbon cycling patterns. In non-peatland areas, losses of carbon from fire affected forest vegetation exceed greatly soil carbon losses, but on carbon-rich substrates, e.g. peat, combustion losses can be considerable. Peatland fires make a major contribution to atmospheric emissions of greenhouse gases, fine particular matter and aerosols and thus contribute to climate change as well as presenting a problem for human health. The scale of emissions is unlikely to reduce in coming decades, since climate modelling studies have predicted that parts of this region will experience lower rainfall in future and greater seasonality. Protecting the rainforests of this region from further fire disasters should be at the top of the global environmental agenda, with highest priority given to peatland areas
Denial of long-term issues with agriculture on tropical peatlands will have devastating consequences
Non peer reviewe
Changes in vegetation and rainfall patterns in sub-Saharan Africa over the last decade observed by satellites - a national and sub-national synthesis
The African Monitoring of the Environment for Sustainable Development (AMESD) programme, a common initiative of the European Commission (EC) and the African Union Commission, is intended to extend the operational use of Earth Observation technologies and data to environmental and climate monitoring applications. The Natural Resource Monitoring in Africa (NARMA) core information service of the EU project Geoland-2 (http://www.gmesgeoland.info/) provides technical support to AMESD in developing an environmental monitoring capacity over African countries for the needs of the EC services and for regional and continental EC partners in African countries. Recently, there is an increased need in environmental information for the implementation of environmental issues in international cooperation policy. To date, however, decision makers tend to use non-spatial indicators of environmental condition and human impact. Thus, there is a demand to develop new environmental indicators based on Earth Observation derived data and gain user acceptance for them.JRC.H.5-Land Resources Managemen
Identification of environmental anomaly hot spots in West Africa from time series of NDVI and rainfall
Studies of the impact of human activity on the vegetation dynamics in the Sahelian belt of Africa have been recently re-invigorated by new scientific findings that highlighted the primary role of climate in the drought crises of the 70-80s. Time series of satellite observations allowed identifying regreening of the Sahelian belt that indicate no noteworthy human effect on vegetation dynamics at sub continental scale from 80s to late 90s. However, several regional/local crises related to natural resources occurred in the last decades despite the re-greening thus underlying that more detailed studies are needed. This study contributes to the understanding of climate and human impacts on the vegetation in the Sahelian region in the last decade (1998-2010). The use of time-series of SPOT-VGT NDVI and FEWS-RFE rainfall estimates allowed us to analyze vegetation and rainfall trends and to identify local anomalous situations. Trend analysis has been conducted to map a) areas where vegetation has been significantly decreasing or increasing due to changes in rainfall patterns and b) anomalous hot spot zones where vegetation dynamics could not be fully explained by changes of rainfall patterns. Multi-temporal analysis of Landsat images allows us to evaluate the reliability of the identified trends and to provide an interpretation of some example hot spots. The frequency distribution of the anomalous situations among the land cover class of the GlobCover map shows that, at the regional scale, environmental degradation occurs mainly in herbaceous vegetation covers where pastoral and cropping practices are often critical due to low and very unpredictable rainfall. The results of this study show that even if a general positive re-greening trend due to increased rainfall is evident for the entire Sahel, some local anomalous hot spots exist and can be explained by human factors such as population growth whose level reaches the ecosystem carrying capacity as well as population displacement leading to vegetation recovery.JRC.H.5-Land Resources Managemen
A conceptual model for assessing rainfall and vegetation trends in Sub-Saharan Africa from satellite data
Policy makers, governments and aid agencies require operational environmental monitoring in support of evidence-based policy-making and resource deployment in crisis situations. For Africa, at sub-continental scale this is only feasible with a large network of automated meteorological stations, a large number of highly coordinated field observers or satellite remote sensing. This study provides a conceptual framework to understand satellite-derived indicators of rainfall and vegetation trends over Africa. It attributes observed vegetation changes to climatic and non-climatic drivers. A decade of annual rainfall and vegetation data over sub-Saharan Africa was analysed using satellite-based rainfall estimates (FEWSNET RFE 2.0) from NOAA’s Climate Prediction Centre and the Normalised Difference Vegetation Index (NDVI) obtained from the SPOT-VEGETATION sensor. Rainfall and vegetation greenness trends were analysed for 759 administrative regions of sub-Saharan Africa to identify those regions that have experienced a negative, positive or stable rainfall/vegetation trend over the period 2001-2010. The character of the relationship between the rainfall and NDVI trends were examined to identify areas subject to climatic and non-climatic changes. Regions where increasing rainfall was associated with vegetation greening were found in West Africa, Central African Republic, West Cameroon and north-eastern part of South Africa, whereas areas with evidence of climatic degradation were located in Southern Madagascar, Nigeria, Kenya and southern part of South Africa. The monitoring concept described here is implemented in the European Commission, serving the needs of both European services and African institutions.JRC.H.5-Land Resources Managemen
A spaced based solution for monitoring land conditions in sub-Saharan Africa
The African Monitoring of the Environment for Sustainable Development (AMESD) programme is a partnership between the European Union and the African Union Commission. It extends the operational use of Earth Observation to environmental and climate monitoring applications. There is an increasing need for environmental information for the implementation of international cooperation policies such as aid and development. Satellites provide an operational and cost-effective way to obtain systematic information on the land condition at the continental and regional scale in Africa.JRC.H.5-Land Resources Managemen
Denial of long-term issues with agriculture on tropical peatlands will have devastating consequences
The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought together over 1000 international peatland scientists and industrial partners from across the world (“International Peat Congress with over 1000 participants!,” 2016). The congress covered all aspects of peatland ecosystems and their management, with a strong focus on the environmental, societal and economic challenges associated with contemporary large-scale agricultural conversion of tropical peat.
However, recent encouraging developments towards better management of tropical peatlands have been undermined by misleading newspaper headlines and statements first published during the conference. Articles in leading regional newspapers (“Oil palm planting on peat soil handled well, says Uggah,” 2016; Cheng & Sibon, 2016; Nurbianto, 2016a, 2016b; Wong, 2016) widely read across the region, portrayed a general consensus, in summary of the conference, that current agricultural practices in peatland areas, such as oil palm plantations, do not have a negative impact on the environment. This view is not shared by many scientists, or supported by the weight of evidence that business-as-usual management is not sustainable for tropical peatland agriculture.
Peer-reviewed scientific studies published over the last 19 years, as reflected in the Intergovernmental Panel on Climate Change (IPCC) Wetland Supplement on greenhouse gas inventories, affirms that drained tropical peatlands lose considerable amounts of carbon at high rates (Drösler et al., 2014). Tropical peat swamp forests have sequestered carbon for millennia, storing a globally significant reservoir below ground in the peat (Page et al., 2011; Dommain et al., 2014). However, contemporary agriculture techniques on peatlands heavily impact this system through land clearance, drainage and fertilization, a process that too often involves fire. Along with biodiversity losses driven by deforestation (Koh et al., 2011; Posa et al., 2011; Giam et al., 2012), the carbon stored in drained peatlands is rapidly lost through oxidation, dissolution and fire (Couwenberg et al., 2009; Hirano et al., 2012; Ramdani & Hino, 2013; Schrier-Uijl et al., 2013; Carlson et al., 2015; Warren et al., 2016). Tropical peat fires are a major contributor to global greenhouse gas emissions and produce transboundary haze causing significant impacts on human health, regional economies and ecosystems (Page et al., 2002; Marlier et al., 2012; Jaafar & Loh, 2014; Chisholm et al., 2016; Huijnen et al., 2016; Stockwell et al., 2016). With future El-Niño events predicted to increase in frequency and severity (Cai et al., 2014) and with fire prevalence now decoupled from drought years (Gaveau et al., 2014), future large scale fire and haze events are imminent given the extensive areas of now drained fire prone drained peatlands (Kettridge et al., 2015; Turetsky et al., 2015; Page & Hooijer, 2016).
In reality, just how much of the estimated 69 gigatonnes of carbon (Page et al., 2011) stored in Southeast Asian tropical peatlands is being lost due to agricultural operations under the current management regime is still uncertain. Of great concern is that none of the agricultural management methods applied to date have been shown to prevent the loss of peat and the associated subsidence of the peatland surface following drainage (Wösten et al., 1997; Melling et al., 2008; Hooijer et al., 2012; Evers et al., 2016). Recent projections suggest that large areas of currently drained coastal peatlands will become un-drainable, and progressively be subjected to longer periods of inundation by river and ultimately sea water (Hooijer et al., 2015a, 2015b; Sumarga et al., 2016). With growing risk of saltwater intrusion, agriculture in these coastal lands will become increasingly untenable, calling into question the very notion of “long-term sustainability of tropical peatland agriculture”.
A more accurate view of drained peatland agriculture is that of an extractive industry, in which a finite resource (the peat) is ‘mined’ to produce food, fibre and fuel, driven by global demand. In developing countries with growing populations, there are strong socio-economic arguments for exploiting this resource to support local livelihoods and broader economic development (Mizuno et al., 2016). However, an acceptance that on-going peat loss is inevitable under this scenario. Science-based measures towards improved management, including limitations on the extent of plantation development, can be used to minimise the rate of this peat loss (President of Indonesia, 2011). Such an evidence-based position, supported with data and necessary legal instruments are needed for sustainable futures. The scientifically unfounded belief that drained peatland agriculture can be made ‘sustainable’, and peat loss can be halted, via unproven methods such as peat compaction debilitates the effort to find sustainable possibilities. To a large extent, the issues surrounding unsustainable peatland management have now been recognized by sections of industry (Wilmar, 2013; APP, 2014; Cargill Inc., 2014; Mondelēz International, 2014; Sime Darby Plantation, 2014; APRIL, 2015; Olam International, 2015), government (President of Indonesia, 2014, 2016; Mongabay, 2015; Mongabay Haze Beat, 2015; Hermansyah, 2016) and consumers (Wijedasa et al., 2015). In recognition of the constraints and risks of peatland development, many large and experienced oil palm and pulpwood companies have halted further development on peat and introduced rigorous management requirements for existing peatland plantations(Lim et al., 2012). However, the denial of the empirical basis calling for improved peatland management remains persistent in influential policy spaces, as illustrated by the articles reporting on the conference (“Oil palm planting on peat soil handled well, says Uggah,” 2016; Cheng & Sibon, 2016; Nurbianto, 2016a, 2016b).
The search for more responsible tropical peatland agriculture techniques includes promising recent initiatives to develop methods to cultivate crops on peat under wet conditions (Giesen, 2015; Dommain et al., 2016; Mizuno et al., 2016). While a truly sustainable peatland agriculture method does not yet exist, the scientific community and industry are collaborating in the search for solutions(International Peat Society, 2016), and for interim measures to mitigate ongoing rates of peat loss under existing plantations. Failing to recognize the devastating consequences of the current land use practices on peat soils and failing to work together to address them could mean that the next generation will have to deal with an irreversibly altered, dysfunctional landscape where neither environment nor society, globally or locally, will be winners.JRC.D.1-Bio-econom