Tag Archives: Environment

SPECIAL REPORT ON GLOBAL WARMING OF 1.5ºC / INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE, December 2018, SUMMARY STATEMENT FOR AFRICA

From Chapter 3, p. 197, Box 3.1 | Sub-Saharan Africa: Changes in Temperature and Precipitation Extremes,

Sub-Saharan Africa has experienced the dramatic consequences of climate extremes becoming more frequent and more intense over the past decades (Paeth et al., 2010; Taylor et al., 2017).

In order to join international efforts to reduce climate change, all African countries signed the Paris Agreement. In particular, through their nationally determined contributions (NDCs), they committed to contribute to the global effort to mitigate greenhouse gas (GHG) emissions with the aim to constrain global temperature increases to ‘well below 2°C’ and to pursue efforts to limit warming to ‘1.5°C above pre-industrial levels’. The target of limiting global warming to 1.5°C above pre-industrial levels is useful for conveying the urgency of the situation. However, it focuses the climate change debate on a temperature threshold (Section 3.3.2), while the potential impacts of these global warming levels on key sectors at local to regional scales, such as agriculture, energy and health, remain uncertain in most regions and counries of Africa (Sections 3.3.3, 3.3.4, 3.3.5 and 3.3.6).

Weber et al. (2018) found that at regional scales, temperature increases in sub-Saharan Africa are projected to be higher than the global mean temperature increase (at global warming of 1.5°C and at 2°C; see Section 3.3.2 for further background and analyses of climate model projections).

Even if the mean global temperature anomaly is kept below 1.5°C, regions between 15°S and 15°N are projected to experience an increase in hot nights, as well as longer and more frequent heatwaves (e.g., Kharin et al., 2018). Increases would be even larger if the global mean temperature were to reach 2°C of global warming, with significant changes in the occurrence and intensity of temperature extremes in all sub-Saharan regions (Sections 3.3.1 and 3.3.2; Figures 3.4, 3.5 and 3.8).

West and Central Africa are projected to display particularly large increases in the number of hot days, both at 1.5°C and 2°C of global warming (Section 3.3.2). This is due to the relatively small interannual present-day variability in this region, which implies that climate-change signals can be detected earlier there (Section 3.3.2; Mahlstein et al., 2011).

Projected changes in total precipitation exhibit uncertainties, mainly in the Sahel (Section 3.3.3 and Figure 3.8; Diedhiou et al., 2018). In the Guinea Coast and Central Africa, only a small change in total precipitation is projected, although most models (70%) indicate a decrease in the length of wet periods and a slight increase in heavy rainfall. Western Sahel is projected by most models (80%) to experience the strongest drying, with a significant increase in the maximum length of dry spells (Diedhiou et al., 2018). Above 2°C, this region could become more vulnerable to drought and could face serious food security issues (Cross-Chapter Box 6 and Section 3.4.6 in this chapter; Salem et al., 2017; Parkes et al., 2018). West Africa has thus been identified as a climate-change hotspot with negative impacts from climate change on crop yields and production (Cross-Chapter Box 6 and Section 3.4.6; Sultan and Gaetani, 2016; Palazzo et al., 2017). Despite uncertainty in projections for precipitation in West Africa, which is essential for rain-fed agriculture, robust evidence of yield loss might emerge. This yield loss is expected to be mainly driven by increased mean temperature, while potential wetter or drier conditions – as well as elevated CO2 concentrations – could modulate this effect (Roudier et al., 2011; see also Cross-Chapter Box 6 and Section 3.4.6).

Using Representative Concentration Pathway (RCP)8.5 Coordinated Regional Climate Downscaling Experiment (CORDEX) scenarios from 25 regional climate models (RCMs) forced with different general circulation models (GCMs), Klutse et al. (2018) noted a decrease in mean rainfall over West Africa in models with stronger warming for this region at 1.5°C of global warming (Section 3.3.4). Mba et al. (2018) used a similar approach and found a lack of consensus in the changes in precipitation over Central Africa (Figure 3.8 and Section 3.3.4), although there was a tendency towards a decrease in the maximum number of consecutive wet days (CWD) and a significant increase in the maximum number of consecutive dry days (CDD).Over southern Africa, models agree on a positive sign of change for temperature, with temperature rising faster at 2°C (1.5°C–2.5°C) as compared to 1.5°C (0.5°C–1.5°C) of global warming.

Areas in the south-western region, especially in South Africa and parts of Namibia and Botswana, are expected to experience the largest increases in temperature (Section 3.3.2; Engelbrecht et al., 2015; Maúre et al., 2018). The western part of southern Africa is projected to become drier with increasing drought frequency and number of heatwaves towards the end of the 21st century (Section 3.3.4; Engelbrecht et al., 2015; Dosio, 2017; Maúre et al., 2018). At 1.5°C, a robust signal of precipitation reduction is found over the Limpopo basin and smaller areas of the Zambezi basin in Zambia, as well as over parts of Western Cape in South Africa, while an increase is projected over central and western South Africa, as well as in southern Namibia (Section 3.3.4). At 2°C, the region is projected to face robust precipitation decreases of about 10–20% and increases in the number of CDD, with longer dry spells projected over Namibia, Botswana, northern Zimbabwe and southern Zambia. Conversely, the number of CWD is projected to decrease, with robust signals over Western Cape Maúre et al., 2018). Projected reductions in stream flow of 5–10% in the Zambezi River basin have been associated with increased evaporation and transpiration rates resulting from a rise in temperature ( Section 3.3.5; Kling et al., 2014), with issues for hydroelectric power across the region of southern Africa.

For Eastern Africa, Osima et al. (2018) found that annual rainfall projections show a robust increase in precipitation over Somalia and a less robust decrease over central and northern Ethiopia (Section 3.3.3). The number of CDD and CWD are projected to increase and decrease, respectively (Section 3.3.4). These projected changes could impact the agricultural and water sectors in the region (Cross-Chapter Box 6 in this chapter and Section 3.4.6).

Posted in Featured | Tagged , | Leave a comment

CLIMATE CHANGE WILL AFFECT DEVELOPING COUNTRIES MORE THAN RICH ONES

Temperatures in tropical climates will become far more variable.

Original Article: Climate Change and Africa

By THE DATA TEAM, The Economist, May 9th 2018

GLOBAL warming is often used as a synonym for climate change, and most discussions of the topic focus on the expected increase in average global temperatures. However, the frequency and severity of individual, catastrophic weather events depend heavily on the variability of temperatures as well as their mean. The larger the swings, the more often extremely hot or cold conditions can wreak havoc.

Unfortunately, according to a new study by Sebastian Bathiany of Wageningen University and three other scientists, poor countries are not only predicted to bear the brunt of the increase in average temperatures, but also to suffer from higher variation. Their paper finds that, as the planet warms, soil in areas near the equator will dry up, reducing its ability to dampen temperature swings. This problem is expected to be especially acute in the Amazon rainforest. Consequently, the authors expect the standard deviation of monthly temperatures to increase by nearly 20% in Brazil.

In contrast, countries in the northern latitudes, which are mostly rich, will not be affected nearly as much by changes in soil moisture. Far from the equator, countries will actually see smaller temperature fluctuations, because of changing atmospheric patterns. In terms of both means and variances, the countries that bear the most historical responsibility for climate change are likely to be the ones least harmed by its consequences.

Posted in Featured | Tagged , | Leave a comment

LAKE CHAD: THE WORLD’S MOST COMPLEX HUMANITARIAN DISASTER

Boko Haram, climate change, predatory armies, and extreme hunger are converging on a marginalized population in Central Africa.

The New Yorker, December 4. 2017

By: Ben Taub

Original Article: The World’s Most Complex Humanitarian Disaster

Chad was named for a mistake. In the eighteen-hundreds, European explorers arrived at the marshy banks of a vast body of freshwater in Central Africa. Because locals referred to the area as chad, the Europeans called the wetland Lake Chad, and drew it on maps. But chad simply meant “lake” in a local dialect. To the lake’s east, there was a swath of sparsely populated territory—home to several African kingdoms and more than a hundred and fifty ethnic groups. It was mostly desert. In the early nineteen-hundreds, France conquered the area, called it Chad, and declared it part of French Equatorial Africa.

A few years later, a French Army captain described Lake Chad, which was dotted with hundreds of islands, as an ecological wonder and its inhabitants as “dreaded islanders, whose daring flotillas spread terror” along the mainland. “Their audacious robberies gave them the reputation of being terrible warriors,” he wrote. After his expeditions, the islanders were largely ignored. “There was never a connection between the people who live in the islands and the rest of Chad,” Dimouya Souapebe, a government official in the Lake Region, told me.

Moussa Mainakinay was born in 1949 on Bougourmi, a dusty sliver in the lake’s southern basin. Throughout his childhood and teen-age years, he never went hungry. The cows were full of milk. The islands were thick with vegetation. The lake was so deep that he couldn’t swim to the bottom, and there were so many fish that he could grab them with his hands. The lake had given Mainakinay and his ancestors everything—they drank from it, bathed in it, fished in it, and wove mats and baskets and huts from its reeds.

In the seventies, Mainakinay noticed that the lake was receding. There had always been dramatic fluctuations in water level between the rainy and the dry seasons, but now it was clear that the mainland was encroaching. Floating masses of reeds and water lilies began to clog the remaining waterways, making it impossible to navigate old trading routes between the islands.

Lake Chad is the principal life source of the Sahel, a semiarid band that spans the width of Africa and separates the Sahara, in the north, from the savanna, in the south. Around a hundred million people live there. For the next two decades, the entire region was stricken with drought and famine. The rivers feeding into Lake Chad dried up, and the islanders noticed a permanent decline in the size and the number of fish.

Then a plague of tsetse flies descended on the islands. They feasted on the cows, transmitting a disease that made them sickly and infertile, and unable to produce milk. For the first time in Mainakinay’s life, the islanders didn’t have enough to eat. The local medicine man couldn’t make butter, which he would heat up and pour into people’s nostrils as a remedy for common ailments. Now, when the islanders were sick or malnourished, he wrote Quranic verses in charcoal on wooden boards, rinsed God’s words into a cup of lake water, and gave them the cloudy mixture to drink. By the end of the nineties, the lake, once the size of New Jersey, had shrunk by roughly ninety-five per cent, and much of the northern basin was lost to the desert. People started dying of hunger.

In 2003, when Mainakinay was fifty-four years old, he became the chief of Bougourmi. He was proud of his position, but not that proud; his grandfather had presided over more than four hundred islands—until the government stripped the Mainakinays of their authority as Chiefs of the Canton, a position that they had held for more than two hundred years. The center of power was moved to the town of Bol, on the mainland. The islanders were of the Boudouma tribe; the mainlanders were Kanembou. They didn’t get along.

Other political developments were more disruptive. Colonial administrators had drawn the boundaries of Chad, Cameroon, Nigeria, and Niger right through tiny circles of huts on the islands. When these nations enforced their borders, the fishermen and cattle herders of Bougourmi, which is in Chad, were cut off from the lake’s biggest market, which is in Baga, on the Nigerian shoreline. In the mid-aughts, hungry and desperate, they turned to foraging in the bush for fruit and nuts. Then they began to run out of fruit and nuts.

Continue Reading:

Posted in Featured | Tagged , , , , , | Leave a comment