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Are human actions making natural disasters more destructive?

By Matt Ford, for CNN
Heavily engineered irrigation could have made the floods worse in Pakistan.
Heavily engineered irrigation could have made the floods worse in Pakistan.
  • Devastation of floods in Pakistan exacerbated by land management
  • Extensive engineering of irrigation, human migration to flood-prone areas worsen disaster effects
  • Simple and often traditional farming and forestry practices can reduce flood effects

(CNN) -- As Pakistan struggles to recover after one of the worst floods in its history, questions are already being asked about how human decisions may have exacerbated the effects of this natural disaster.

"Human activities have made the impacts of disasters more destructive," Claire Seaward, Oxfam, told CNN.

In Pakistan, as in many countries around the world, a growing population has forced more and more people to live in vulnerable coastal areas and floodplains.

"Increasingly, people are choosing unsafe areas to live and there is mass congregation into increasingly concentrated areas... as people look for access to water and land to grow food," says Seaward.

As scientists predict that climate change will cause a more unstable and volatile weather, it seems essential that governments across the world learn the lessons of Pakistan.

A lot of traditional knowledge has been lost in the effort to improve and modernize agriculture.
--James Dalton, IUCN

One of the problems is that a rising population places demands on the landscape in terms of food production, and in Pakistan agricultural irrigation projects altered the natural flow of water -- with disastrous consequences.

"In order to increase the amount of agricultural land available and bring benefits of a better food supply to millions of people, they have put in a lot of hardcore engineering," James Dalton, Water Management Advisor, International Union for Conservation of Nature told CNN.

"This has many benefits and makes people feel safe. But with that kind of irrigation it is only possible to plan for a certain percentage increase in water and when you get an event like this, it's impossible to prepare.

"Then suddenly you have this infrastructure intended to move water around more efficiently, and it vastly increases flow rates, which is what has done a lot of the damage we are seeing."

Pakistan is a natural disaster-prone country -- in the past five years it has had two major earthquakes and now one of the worst floods in history -- and NGOs argue the government must do more to plan for the worst.

"For the government to ensure Pakistan can properly prevent and respond to these disasters it needs to do two things," says Seaward.

"Firstly, [it] needs to prioritize disaster risk reduction in all its planning, including land use... [this] needs to focus on the prevention, preparedness, vulnerability reduction and mitigation as well as what to do once a disaster has struck.

"Secondly, the government needs to back up this planning with actual investment of resources to deliver these plans."

Floods begin when heavy rain falls upstream and understanding the relationship between what happens in the mountains and how this impacts the floodplain is essential. For example, soil erosion and deforestation both increase the amount of silt in rivers, which in turn clogs up irrigation channels and makes flooding worse -- but simple changes in land management can dramatically reduce this.

"It's very difficult when you get such heavy rain -- there will always be erosion -- but there are things that can be done to minimize this," says Dalton.

"For example, it's important to plant crops across slopes, rather than down the slope; perhaps even use terracing to preserve the slope.

"A lot of this is traditional knowledge, but in the effort to improve and modernize agriculture it's been forgotten.

"Also, many areas of wetland have also been drained to create more productive agricultural land. But in times of flooding this act as natural sinks and actually capture and hold water."

Elsewhere in the world there are examples of countries in a similar position to Pakistan that are already learning the lessons of recent disastrous floods.

Mozambique has experienced three major floods in the last decade. The most recent one in 2008 was more extensive than in 2007 and in the major disaster in 2000, when around 800 people died.

"The disaster has been exacerbated by the fact that poor people, in the hope of earning more, take the risk of living and farming in the more fertile low-lying land near the river," says Seaward.

"When the floods come, they lose all they have and are forced further into poverty. Without proper embankment protections, early warning and evacuation systems, people are hit hard; losing their food supplies, their homes and their crops."

However, there are signs that Mozambique is learning the lessons -- during the 2008 flooding the death toll was significantly reduced by effective planning and disaster risk reduction programs.

"There is still a long way to go, but the people are taking the necessary steps to improve their safety and the land around them," says Seaward.

Across South Asia, Oxfam is working with partner organizations in flood-prone areas to form local disaster-preparedness.

"In April 2007, flash floods and mud-slides caused by heavy rains and snowmelts affected large areas of northern Afghanistan, causing much death and devastation," says Seaward.

"But in the village of Dari-Souf Payan in Samangan [where Oxfam works] suffered only a single casualty and limited damage to property."

It's not only in the developing world where approaches to mitigating the effects of natural disasters are changing. In parts of the United States, Germany and the United Kingdom, authorities are actually encouraging the regeneration of salt marsh -- that was previously drained to create agricultural land -- as a way of mitigating flooding.

"With climate change and rising seas this will become more and more important," says Dalton.

"Traditionally we protect ourselves against the sea with concrete -- and that's still important, but as the climate becomes more varied we will have to become more varied in our approach."