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The East African : Nov 14th 2015
26 The EastAfrican OUTLOOK NOVEMBER 14-20,2015 D E VE LO PME N T Scientists turn to insects in fight against climate change The p≥oject will also guide national pest management p≥og≥ammes By CLIFFORD GIKUNDA Special Correspondent T he impact of climate change on insects may be reflected in their distribution, activity, number of generations and breeding cycle. However, predicting the direction and pace of climate change, as well as its effect on insects, is difficult and often inaccurate. Scientists from the Inter- national Potato Centre (CIP), Bioversity International, International Centre for Tropical Agriculture (CIAT) and the International Institute for Tropical Agriculture (IITA) are working on climate resilience mechanisms to predict and monitor the behaviour of insects at different temperatures and the impact on food crops in the Great Lakes region. “We want to ascertain what pests and diseases could come to the region and which endemic ones could evolve into something else when it becomes warmer,” Joshua Okonya of International Potato Centre, Uganda, told The EastAfrican. The project will also guide national pest management programmes in an effort to increase natural control of the new pests and reduce the PROJECTS Joshua Okonya, a scientist with the International Potato The project involves national research institutes including L’Institut nNational pour l’Etude et la Recherché Agronomique (the national research institute of the Democratic Republic of abuse of pesticides by farmers. According to scientists, a rise in temperature would mean a shorter life cycle for the insects, more fertile females that will produce more eggs within a shorter time, thus an explosion of the insect colonies that will be detrimental to the food security in the region. “Being new pests, they would not have natural enemies to reduce the populations, thus their increase would pose a risk to the whole region” said Dr Norma Mujica, an entomologist from Lima, Peru. Centre, at the Ruhengeri Mountains monitoring station. Pic: CLIFFORD GIKUNDA Congo), L’ Institut des Sciences Agronomiques du Burundi, the National Agricultural Research Organisation, Uganda and the Rwanda Agricultural Board. The climate resilience in modelling involve setting up of stations to perform accurate insect mapping. “This monitoring will help in guiding scientists and policymakers plan by understanding the weather and putting up adaptation measures to deal with both the existing pests in the region and the ones that are likely to emerge in increased temperatures” said Dr Mujica. In Rwanda the scientists, picked the Ruhengeri Mountains, where 25 stations were set up from up the mountain high altitude of 2600 metres above sea level to a lower much warmer of 1400 metres. In Burundi, 27 stations have been set up between 2400 metres elevation to 800 metres in the Rusizi valley near Bujumbura These are highly populated areas, food constrained and prone to a large number of pets and diseases due to its wide range of agro ecologies and cropping systems. The stations are equipped with advanced thermometers and rain gauges, which monitor the temperature, humidity and rainfall every one hour. “An increase in tempera- ture of as little as two degrees will affect insect vector activity at higher elevations; in bananas, there will be more aphids for the transmission of Banana Bunchy Top Virus (BBTV) and a wide range of insect species that are hosts for the bacterial xanthomonas wilt (BXW),” said Dr Guy Blomme, a specialist in integrated banana systems at Bioversity International in Addis Ababa, Ethiopia. Banana Bunchy Top Virus is the most serious and destructive viral disease affecting banana and plantain in Africa, Australia and Southeast Asia. Before 2001, BXW was found only in Ethiopia, but it has since spread to the Great Lakes region, in the Rusizi valley in Burundi, along the Congo River in the DRC, in eastern Uganda and western Kenya. According to Dr Blomme, there is limited insect vector transmission at elevations higher than 1700metres for BXW, and not much aphid transmission occurs for BBTD above 1,500 metres, but this could change with increasing temperatures. The increased insect colo- An increase in temperature of as little as two degrees will affect insect vector activity at higher elevations.” nies will affect many crops including cassava with an increase in Cassava Brown Streak Virus, an explosion in numbers of the sweet potato weevil and white flies that transmit viruses. In Irish potato, there would be an increase in the leaf minor fly. In maize, the maize lethal necrosis disease currently affecting large swathes of maize growing areas in Kenya could find its way to the whole East African region. The disease is a combination of two viruses, the Maize Chlorotic Mottle Virus and any of the cereal viruses in the Potyviridae group, like the Sugarcane Mosaic Virus, Wheat Streak Mosaic Virusor Maize Dwarf Mosaic Virus. Greenhouses are said to increase pollution. Picture: File G≥eenhouse gases hit new milestone By JOBY WARRICK The Washingtopn Post GREENHOUSE GASES in the Earth’s atmosphere reached another grim milestone earlier this year as carbon dioxide levels surpassed the symbolic threshold of 400 parts per million across much of the planet, the premier global meteorological association confirmed in a report to be released Monday. Figures compiled by the World Meteorological Organisation showed strong growth — and new records — in the concentrations of all three of the most important heat-trapping gases, continuing a long-term trend with ominous implications for climate change, the group said. The report is likely to add to concerns about global warming in a year that climate experts say is almost certain to surpass 2014 as the hottest year in recorded history. “We are moving into uncharted territory at a frightening speed,” WMO secretary general Michel Jarraud said of the report’s findings. The WMO maintains the world’s biggest network of sensors detecting changes in the makeup of the Earth’s atmosphere. For decades it has tracked rising concentrations of greenhouse gases such as carbon dioxide, a naturally occurring chemical compound that is vital for plant life and also acts as an insulating blanket, trapping the sun’s heat and making the planet warmer than it would otherwise be. With the burning of fossil fuels, levels of atmospheric carbon dioxide have risen steadily, soaring from about 278 ppm during pre-industrial times to above 390 ppm by the start of the current decade. Many scientists contend that the carbon dioxide lev- els should remain well below 400 ppm to avoid longterm disruptions to the Earth’s climate. But since 2012, several of the WMO’s 125 individual monitoring stations have detected readings above that threshold. The global average climbed to 397.7 ppm in 2014, the WMO report said, and then, in early 2015, it exceeded 400 ppm for the first time since record-keeping began, the organisation’s data shows. The level then dipped, as usual, with the arrival of the spring growing season in the Northern Hemisphere, when trees and other plants take carbon dioxide out of the atmosphere. But WMO officials say the planetary average is expected to remain above 400 parts per million beginning in 2016. “We will soon be living with globally averaged CO2 levels above 400 parts per million as a permanent reality,” Jarraud said. Hotter temperatues The long-term implica- tions for the planet, he said, include “hotter global temperatures and more extreme weather events” as well as melting ice, rising sea levels and increased acidity in oceans. “It is an invisible threat, but a very real one,” he said. The WMO report, an an- nual compilation of monitoring data from the organisation’s Global Atmospheric Watch programme, shows carbon dioxide concentrations rising by 0.5 per cent from 2013 to 2014, roughly on par with the average annual increase over the past decade. But two other key greenhouse gases — methane and nitrous oxide — appear to be increasing at a fast rate, the report said. Methane increased by 9 parts per billion from 2013 to 2014, compared with an average annual increase of 4.7 ppb, the report said.
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