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Tuesday, February 24, 2009

Africa Cannot Ignore Climate Change

Today climate change adaptation and mitigation is no longer merely a policy aspiration-it is an imperative. The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) concludes that climate change is unequivocal. The report also reaffirms that climate change will have disproportionately harmful effects in Africa where human health and agriculture will be under particular threat from climate change. Failing farms will erode the asset base, increase poverty as households invest their little income and meager savings just to survive. As a result warmer climates, drought, low agricultural productivity, millions of people are potentially at risk of hunger, malnutrition, water related and vector borne diseases.

The impacts of climate change in Africa relate to several factors associated with the vulnerability of African societies and the sensitivity of a fragile environment. Important factors here are high dependency on low technology rain-fed subsistence agriculture, rapid population growth, limited surface water, resource conflict, poor infrastructure, disease burden and poverty. Countries in Sub-Saharan Africa in general, have a low institutional and financial capacity to adapt to changes.

Reduction of vulnerability to climate change is clearly a more realistic adaptation policy for Sub-Saharan Africa. This vulnerability relates to several critical sectors: the dependency on biomass constitutes a serious energy management issue in Africa, often leading to local deforestation and threatens water supplies and biodiversity. Thus, increasing the range of substitution possibilities for household energy consumption constitutes an adaptation measure. In rain-fed agriculture, small climatic changes often have profound implications on household food security, nutrition and income. Agricultural research promoting drought-resistant seeds or climate-adapted species or water use efficiency, or developing new sources of income for households can reduce vulnerability. Climate change and variability is also expected to lead to changes in disease transmission, range, prevalence and incidence.

Food insecurity and malnutrition are also likely to be further aggravated by climate change interacting with other multiple stressors such as emerging and re-emerging vector-and water-borne diseases, HIV/AIDS, malaria, poverty, conflict and weak institutions weak institutions and limited knowledge and capacity to respond to the impacts of climate change.

Climate change therefore threatens long term sustainability and attainment of the Millennium Development Goals for 2015 in Sub Saharan Africa. Hence, improved adaptation capability will be of must be a higher order priority among Sub-Saharan African countries.

Thursday, February 19, 2009

Forests, Water and People: Myths, Misunderstandings, Misinterpretations and Misinformation

Today, forests and their role in regulating water supply and water quality remains hotly debated both in the scientific and public policy arena. More research and accurate communication of research findings is needed to ascertain what trees can and cannot do to meet the challenges a hot and crowded planet will face with regard to water supply and water quality.

For nearly a century, public education, forest and water policies were based on the assumption that under any hydrological and ecological circumstance, forest is the ideal land cover to maximize water yield, regulate seasonal flows and ensure high water quality.

Following this assumption, forest conservation and reforestation in upland watersheds was deemed the most effective measure to guarantee sustained water supply for domestic, agricultural and industrial use as well as protecting downstream communities from ravaging floods.

It is not surprising therefore that public policy making in environment and conservation has been based solely on the notion of more trees more water, and in some cases, this has been stretched to the belief that more trees would lead inevitably to more rain.

Some of these earlier assertions are counter intuitive. For instance, forested landscapes are in fact major users of water. Tree canopies reduce groundwater and stream flow through interception of precipitation, evaporation and transpiration.

Previous generalizations about the benefits of upstream forest cover on downstream annual and seasonal flows have been found to be misleading.

Both natural and plantation forest use more water than either pasture or cropland. There is therefore no doubt that even partial forest removal will increase downstream water discharge. Removal of heavy water demanding forest cover could be a rational course of action especially in arid areas, as a means of mitigating the effects of drought on dry season stream flow.

It has been shown that extensive reforestation in monsoonal climates can lead to severely diminished stream flows during the dry season that may engender a suite of other problems, potentially offsetting any advantages gained by planting trees. However, there are significant tradeoffs. Deforestation decisions must therefore be weighed against loss of important ecosystem functions besides water supply.

“Forests and Floods: Drowning in Fiction or Thriving on Facts?” , a report by Food and Agriculture Organization (FAO) and the Centre for International Forestry Research (CIFOR) published in 2005 concluded forests can play a role in minimizing runoff that causes localized flooding.
The FAO/CIFOR report further notes that even at the local level, the flood-reducing effects of forests are heavily dependent on soil depth and structure, and saturation levels, not exclusively on the presence of the trees. Impacts of deforestation are evident only at the micro level and in association with short-duration and low-intensity rainfall events.

Hence, the protective role of upstream forest cover against seasonal downstream floods has often been overestimated. This is especially true in connection with major events affecting large river basins.

In Kenya, there is little empirical evidence to demonstrate that recent trends in deforestation in the upland watershed of the Nyando River have exacerbated flood frequency or severity in the Kano plains. We can not demonstrate that the 1997/98 floods in the Nyando River basin were more severe than floods of 1961/62.

The ritual flooding in the Kano plains result largely from a combination of simultaneous discharge peaks of river Nyando and its tributaries, high runoff from the adjacent hills (Nandi escarpment, Nyabondo plateau and Sigowet escarpment), high groundwater tables, lateral river embankments and a lack of storage areas in the lowlands.

Partial or complete removal of tree cover may accelerate water discharge and increase flood risk during the rainy season. But as rainfall duration or intensity increases, or as distance of the rainfall area from the watershed increases, the influence of tree cover on flow regulation decreases.

There are many good and great reasons for reforesting the Nyando and Nzoia river basins or other flood prone basins elsewhere, (e.g. reducing soil loss, keeping sediments out of streams, maintaining biodiversity, carbon sequestration), flood risk reduction or even control is not one of them. Reforestation to prevent or reduce floods and associated land degradation may be effective only at the scale of Katuk Kodeyo gulley basin in Nyakach, Western Kenya.

The scientific debate on the role of trees in the landscape rages on.

In a study published in 2007 by Bradshaw et al., in the journal Global Change Biology, researchers from Charles Darwin University in Australia and the National University of Singapore claimed that a 10 percent increase in deforestation results in a 4-28 percent increase in flood frequency in the countries modelled. These findings were based on data from 56 developing countries.

However, the coarse scale country statistics utilized in this study may mask variation flood frequency and severity due to climate, soils, land use, population density land management and hydrological conditions making it difficult to draw solid conclusions about cause and effect.

Evidence from the Amazon and Yangzte river basins show that reduced infiltration and increased sedimentation contributed to flooding. But deforestation per se did not contribute to reduced infiltration and sediment generation and subsequent flooding. We know that sedimentation and reduced infiltration can be enhanced through better soil and land use management. Again reforestation alone does not necessarily reduce flooding if soil structure and river bed morphology does not change.

The tragedy is that what will grab the attention of policy makers and environmental activists is the claim, without solid empirical evidence, that deforestation amplifies flood risk and severity. A paper published in the international weekly journal of science, Nature, considered the paper by Bradshaw and his colleagues ‘a landmark study that offers strong evidence that forest do reduce frequency and severity of floods.

In Kenya the debate on the link between forests and water resources is perhaps even more intense in the public arena than it is in the scientific arena. All too often, what should a dispassionate debate is mired by stakeholder self interests. The debate is distorted for electoral/political expediency, public policy or for environmental activism.

We all remember too well the state-led humiliation of Nobel laureate Prof. Wangari Maathai in the heady days of her crusade against forest excisions motivated by land grabbing.

“Threats” to the Mau began with the land fragmentation and settlement program of the 1970s when large-scale forest excision began. It would help to look at time-series flow data for all the major rivers that flow from the Mau and relate these to spatial and temporal patterns of deforestation in the Mau Forest Complex.

Today evictions from Kenya’s Mau Forest is based on the notion that uprooting nearly 50,000 smallholder farm families will somehow save Sondu-Miriu hydropower plant and resuscitate Lake Victoria, especially the Winam Gulf, from ecological comatose.

It is for the sake of these voiceless and powerless citizens that we must act now to narrow the gap between research and public policy making and communicate with clarity, the linkages between forests and water to policy makers.

Wednesday, February 18, 2009

Global warming worse than IPCC prediction

New data shows that from 2000 to 2007, greenhouse gas emissions increased far more rapidly than was expected, primarily because developing countries, like China and India, saw a huge surge in electric power generation, almost all of it based on coal. Chris Field, a member of the Intergovernmental Panel on Climate Change (IPCC) told the American Association for the Advancement of Science meeting in Chicago.

According to Chris Field, the trend was likely to continue if more countries turned to coal and other carbon-intensive fuels to meet their energy needs. If so, he said the impact of climate change would be “more serious and diverse” than the IPCC's most recent predictions.

Thursday, February 12, 2009

Charles Darwin: An enduring legacy of ideas and imagination

Happy birthday baby Charles! Two hundred years ago, Charles Darwin was born.

His achievements were outstanding; his science, unmatched. His work transformed our understanding of nature and of ourselves.

He examined the minutiae of nature-the little things of life and life forms. But he also worked on grand ideas such as the abolition of slave trade. He communed with men of high standing and learning. But he also congregated with farmers and pigeon breeders.

Charles Darwin was a quintessential intellectual. He observed, questioned, experimented, incessantly testing and validating his ideas. In 1869, Charles Darwin said to J.D. Hooker "If I lived twenty more years and was able to work, how I should have to modify the Origin, and how much the views on all points will have to be modified! Well it is a beginning, and that is something ….” Sir Joseph Dalton Hooker, botanist, explorer and plant collector was a friend of Charles Darwin.

Charles Darwin is best known for The “Origin of Species”. This book laid the foundations of modern biology. In this volume, Darwin presented extensive and persuasive evidence that all living beings-including the human types-have evolved from a common ancestor. Natural selection, he wrote, was the driver of evolutionary change. Sexual selection, he argued, was an additional force, responsible for spectacular features like the tail feathers of peacocks and big cars for grown men (useless for or even detrimental to) survival but essential for getting dates.

His other works include “The Descent of Man and Selection in Relation to Sex” (1871) and “The Expression of the Emotions in Man and Animals” (1872). I his old age Charles Darwin wrote down his recollections for his own amusement and the interest of his children and their descendants.

As we probe into DNA sequences, we see natural selection acting at the gene level. Our genes bear evidence of our intimate relation with other life forms; from protozoa to ungulates to grains.

Today, advances in research enable us to trace the genetic changes that differentiate us from our primate kin, and demonstrates that significant parts of the human genome validates evolution through natural selection.

It is astounding looking back 200 years, how much Charles Darwin knew, and how far he saw.


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