Climate change in Indonesia: implications for humans and nature

A paper published by the World Wide Fund for Nature (WWF) in Gland, Switzerland, November 2007 

The full paper can be read here: WWF_cc_impact in indonesia_report_en_Nov07 

By Michael Case1, Fitrian Ardiansyah2, Emily Spector3

1Research Scientist, WWF International Climate Change Programme

2Program Director, Climate & Energy WWF-Indonesia

3Brandeis University



Observed climate change (Hulme and Sheard, 1999; Boer and Faqih, 2004):

  • Mean annual temperature has increased by about 0.3°C in Indonesia
  • Overall annual precipitation has decreased by 2 to 3% in Indonesia
  • Precipitation patterns have changed; there has been a decline in annual rainfall in the southern regions of Indonesia and an increase in precipitation in the northern regions
  • The seasonality of precipitation (wet and dry seasons) has changed; the wet season rainfall in the southern region of Indonesia has increased while the dry season rainfall in the northern region has decreased

Projected climate change (Hulme and Sheard, 1999; Boer and Faqih, 2004; Naylor et al., 2007)

  • Warming from 0.2 to 0.3°C per decade in Indonesia
  • Increase in annual precipitation across the majority of the Indonesian islands, except in southern Indonesia where is it projected to decline by up to 15 percent
  • Change in the seasonality of precipitation; parts of Sumatra and Borneo may become 10 to 30% wetter by the 2080’s during December-February; Jakarta is projected to become 5 to 15% drier during June-August
  • 30-day delay in the annual monsoon, 10% increase in rainfall later in the crop year (April-June), and up to 75% decrease in rainfall later in the dry season (July–September)



Water availability

  • Decreased rainfall during critical times of the year may translate into high drought risk, uncertain water availability, and consequently, uncertain ability to produce agricultural goods, economic instability, and drastically more undernourished people, hindering progress against poverty and food insecurity (Wang et al., 2006)
  • Increased rainfall during already wet times of the year may lead to high flood risk, such as, the Jakarta flood on 2 February 2007 that inundated 70,000 houses, displaced 420,440 people and killed 69 people with losses of Rp 4.1 trillion (US$ 450 million) (WHO, 2007)
  • Stronger, more frequent El Niño events will exacerbate drying and/or flooding trends and could lead to decreased food production and increased hunger
  • Delayed wet season (monsoon) and a temperature increase beyond 2.5°C is projected to substantially drop rice yields and incur a loss in farm-level net revenue of 9 to 25% (Lal, 2007)
    sea-level rise
  • Currently increasing at 1-3 mm/year in coastal areas of Asia and is projected to accelerate to a rate of about 5 mm per year over the next century (Cruz et al., 2007)
  • Increase from 13 million to 94 million people flooded annually in South Asia (under very conservative sea-level rise scenarios – 40cm by 2100) (Wassmann et al., 2004)
  • 1 million at risk from flooding and sea-water intrusion due to sea-level rise and declining dry-season precipitation, negatively impacting the aquaculture industry (e.g., fish and prawn industries) and infrastructure along the coasts of South and South-East Asia, (Cruz et al., 2007)

Biodiversity and ecosystem services

  • Up to 50% of Asia’s total biodiversity is at risk (Cruz et al., 2007)
  • 88% loss of coral reefs in Asia in the next 30 years because of warming sea-surface temperatures, sea level rise, and other added stresses (Wilkinson, 2004)
  • Significant declines in fish larvae abundance and large-scale changes in fish habitat, such as skipjack tuna, are projected in the equatorial Pacific (Cruz et al., 2007; Loukos et al., 2003)
  • Massive coral bleaching leading to widespread loss of coral reefs and biodiversity, including the fish that many Indonesians rely on for food and livelihoods
  • Sea-level rise, increased extreme weather events, warming temperatures, and changes in ocean circulation and salinity patterns impacting Indonesia’s marine turtle populations (WWF, 2007a)
  • More frequent forest fires having significant impacts on wildlife habitat and biodiversity and translating into serious economic and domestic and trans-boundary pollution consequences – the economic costs of the droughts and fires in 1997-1998 were about US$ 9 billion (Applegate et al., 2002)
  • Sea-level rise, reduced freshwater flows, and salt-water intrusion, in addition to the existing stresses primarily due to human activities threaten Indonesia’s coastal mangroves (Tran et al., 2005)
  • Changes in species distribution, reproduction timings, and phenology of plants (Cruz et al., 2005)

Human health

  • More frequent and severe heat waves, floods, extreme weather events, and prolonged droughts leading to increased injury, illness, and death
  • Increased vector-borne infections (e.g., malaria and dengue), an expansion of water-borne diseases, such as diarrhea, an increase in infectious diseases, poor nutrition due to food production disruption, ill-health due to social dislocation and migration, and increased respiratory effects from worsening air pollution and burning
  • Increased diarrhoeal disease and endemic morbidity and mortality (Checkley et al., 2000)
  • Rise in severe respiratory problems following an increase in the frequency and spread of wildfires that release toxic gases such as carbon monoxide, ozone, nitrogen dioxide and hydrocarbons
  • A rise in the number of dengue fever cases during the rainy season (PEACE, 2007)
  • More phytoplankton blooms, providing habitats for survival and spread of infectious bacterial diseases, such as, cholera (Pascual et al., 2002)
  • Increased water-borne diseases such as cholera and diarrhoeal diseases (e.g., Giardia, Salmonella, and Cryptosporidium) (McMichael et al., 2003)

Vulnerability and adaptation

  • Water availability and food production are highly sensitive and vulnerable sectors to changes in temperature and precipitation include (Cruz et al., 2007)
  • Prolonged droughts, increased flooding, and more frequent and severe storms may lead to major agricultural losses and a substantial drop in food productivity
  • Increased frequency and severity of El Niño events and fires will impact food production and will the ability of natural systems to provide ecosystem services
  • Warming ocean temperatures, sea-level rise, and increased storms will impact coastal systems by increasing coral bleaching events, changes in fish availability, inundation of coast lines and mangroves, and exacerbating risks to human health affecting millions of people
  • The following can enhance social capital and reduce the vulnerability to climate change:
    • Increase education and technical skills
    • Increase income levels
    • Improve public food distribution
    • Improve disaster preparedness and management and health care systems
    • More integrated agro-ecosystems
    • Increased water storage, water efficiency and re-prioritizing current water use
    • Investment in drought-tolerant and salt-tolerant crops
    • Crop diversification
    • Better early El Niño warning systems
    • Sustainable management of coastal zones
    • Conservation of mangroves
    • Reducing deforestation and protection of forests

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