ستمبر 09, 2013
Pakistan has recently kicked off a country-wide “10 Billion Trees Tsunami” campaign, specifically aimed to counter climate change through a massive afforestation drive. The government envisages this drive will also bring in economic returns as early as 2020. If this drive is carried out with a strategic approach, especially in the tree species planted, it will improve safety and wellbeing of the people manifold, including vitally important flood prevention.
This campaign takes off from the 2014 “Billion Trees Tsunami” afforestation drive that was launched by the provincial government of Khyber Pakhtunkhwa (KPK) as a way to counter the effects of droughts, cloudbursts and storms in that Himalayan region, all worsened by climate change.
Trees and the city
A promising aspect of the new drive is that it is being launched in the most populous cities in its initial phase: Lahore, Karachi, Multan and Peshawar. This is going to play an important role in minimising the Urban Heat Island (UHI) effect (localised increased warming of an urban area due to concentration of concrete buildings and asphalt roads). In cities, the small area covered by trees and other vegetation is shrinking at a rapid pace, as indicated by recent studies based on satellite remote sensing data, worsening the UHI effect. Since vegetation, in particular trees, intercept solar energy, their shade reduces the temperature of surfaces below them and their natural evapotranspiration help maintain cooler conditions and maintain outdoor thermal comfort.
Challenges for the forestation drive
The 10 Billion Trees Tsunami project may face a number of challenges, however. The first will be to ensure survival of the saplings. The authorities can improve the chances of survival by promoting native species that can withstand and naturally regenerate in various ecological regions of Pakistan. As yet, there is no information on which species the government has chosen.
Another challenge is to choose the plantation sites wisely. While the drive will be carried out all over the country, the KPK government has already invested over USD 123 million in support of this project and aims to allocate a further USD 100 million through the year 2020.
Previous examples of forestation
Pakistan will not be the first country to use large-scale afforestation to combat urgent challenges. Michael Wolosin, president of Washington DC based firm Forest Climate Analytics, examined the various afforestation, reforestation and (forest) restoration efforts in India, China and South Korea. According to Wolosin, tree plantation programmes by these three countries, overall, helped remove about 12 billion metric tonnes of atmospheric carbon dioxide in just 20 years.
The afforestation programmes were driven by different issues. South Korea became involved due to soil erosion concerns with subsequent fatal flooding in the 1970s. The country encouraged local communities to undertake forestry programmes, while moving rural populations to cities to lower human pressure on forests.
In China deforestation was driven by massive timber extraction by industry, leading to widespread desertification and the expansion of the Gobi desert onto precious agricultural land. Hence, China launched its Three-North Shelter Forest Programme in 1978 – the world’s largest tree planting which promised to increase the world’s forest cover by a whopping 10%. However, the timber extraction continued to degrade the forests. Then China introduced another large project called Grain for Green Project (GGP) to convert steep cultivated land to forest. These initiatives weren’t effective, due to low tree survival rates in China.
India has provided the most economical solution by providing constant and increasing budgetary support for its forestry efforts.
The role of forests
Forests can play a number of important roles in a climate threatened region. They are natural sinks of carbon dioxide (the main greenhouse gas causing climate change), improve local air and water quality, serve as a line of defence during floods and reduce the effect of droughts by helping recharge groundwater.
A large scale experiment conducted in Wales in the UK concluded that plots planted with broadleaved trees were, on average, 67 times more effective at absorbing surface water runoff compared to grazed grassland. Trees also slow the water flow over a floodplain. The fallen leaves and tree roots hinder surface water flow. The roots also increase soil permeability. This reduces surface flooding as water is absorbed more quickly by the soil in case of floods.
Trees also help to reduce flooding by directly intercepting rainfall and promoting higher soil infiltration rates. In the coastal areas of Pakistan, forests in the form of mangroves are a protection against floods, cyclones and a possible tsunami.
BBC Environmental analyst Roger Harrabin has reported that planting trees in 25-40% of a catchment area can reduce flooding by up to 20%. It enables more sustainable water flows and reduces soil erosion.
The urgent need
According to the latest special report of the Intergovernmental Panel on Climate Change (IPCC), global average temperature change above pre-industrial level is projected to overshoot the 1.5 degrees Celcius mark by some amount well before the end of this century unless urgent steps are taken. Pakistan has been consistently ranked among the ten countries worst affected by climate change. The increased frequency and intensity of extreme climate events during the last two decades in Pakistan, has had serious and long-term adverse impacts on the country.
Available data suggests that the Hindu Kush Himalayas is heating up at a rate faster than the global average, causing an increase in melting rates of Pakistan’s seasonal snow cover and some low elevation glaciers. If accompanied by an intense rainfall event, this can lead to extreme flash flooding, debris flow or glacial lake outburst flood (GLOF), the likes of which have recently been experienced more frequently in the highlands of the country. It also has significant downstream effects in the form of marked changes in irrigation water supplies to Pakistan’s agricultural command areas.
Only large-scale efforts can help mitigate the effects of global warming. To bring the greenhouse gas emissions down to net zero and prevent a climate tipping point, we not only need to quickly reduce emissions, we also need massive afforestation. The 10 Billion Trees Tsunami drive is an important step in this regard, and its successful implementation will be an important signal of Pakistan’s willingness to tackle a problem that confronts both it, and the world.
Haris Mushtaq, Zia Hashmi and Amjad Masood are researchers associated with the Global Change Impact Studies Centre (Water Resources and Glaciology Section), Islamabad, Pakistan.