Engineering: issues, challenges and opportunities for development ...

ENGINEERING FOR DEVELOPMENT: APPLICATIONS AND INFRASTRUCTUREThis issue is still undecided, and while the EU has come up withthe 2ºC target as the maximum that should be allowed, thisis not universally accepted, and there are some who are evenquestioning whether this might be too high, and that maybewe should think in terms of something lower, particularlysince temperature increases correlate closely with some ofthe most threatening impacts of climate change. Climatechange will reduce biodiversity and perturb the functioningof most ecosystems as well as compromising the servicesthey provide. This will have particular impacts on the poorestcommunities in the world who depend particularly on natureand the land, and will also impact upon the ability of societiesand communities to pursue sustainable livelihoods. IPCC hasassessed that 20–30 per cent of plant and animal species areat risk of extinction if increases in global average temperatureexceeds 1.5º–2.5ºC. This is a serious observation that shouldreally make the human race sit up and think, and see how wemight prevent such an outcome, which could very well takeplace in the lifetimes of at least the young generation of today.Turn to some projections of the future: where are temperatureslikely to reach by the end of this century? IPCC hasassessed a number of plausible scenarios in terms of technologicalchanges, economic growth, social changes and institutionalchanges, and we find that at the lower end of thesescenarios a best estimate of 1.8ºC by the end of the century. Atthe upper end of the scenarios – if we have vigorous growthand an increase in emissions of greenhouse gases, we are likelyto end up with an increase of 4.0ºC as our best estimate. Therefore,the future looks something like what is shown in Figure 3,where a large range of possible temperature increases is indicated.However, if one looks at even the lower-most projectionof 1.8ºC, and then combines this with the 0.74ºC increase thattook place during the twentieth century, then it is apparentthat we will likely have a temperature increase of over 2.5ºCby the end of this century above that at the beginning of thecentury. The world has to decide how acceptable this range ofpossible temperature increases will be, and their likely consequencesand impacts.Expected impactsSome ecosystems are highly vulnerable such as coral reefs,marine shell organisms, tundra, arboreal forests, mountainsand Mediterranean regions. We can also identify, as we havedone in the Fourth Assessment Report, some impacts thatcause concern; malnutrition could be exacerbated by thereduced length of the growing season in the Sahelian region.In some countries yields from rain-fed agriculture will be particularlyvulnerable given the fact that there are going to bechanges in precipitation levels as well as patterns. These couldbe reduced by up to 50 per cent by 2020. In one projectionwe have made, between seventy-five million and 250 millionpeople would be exposed to increased water stress in 2020 inAfrica, and we need to remember that climate change addsFigure 1: Graph showing the rise in global temperaturesDifference (°C) from 1961-900.60.40.20.0-0.2-0.4-0.6-0.8Evolution of global mean temperatureGlobal mean temperatureAnnual meanLinear trendsSmoothed series5-95% decadalerror barsPeriod Rate50 0.128±0.026100 0.074±0.018Years °/decade1860 1880 1900 1920 1940 1960 1980 2000Figure 2: Human contribution to climate changeGlobal atmosphericconcentrations ofgreenhouse gasesincreased markedly asresult of human activitiesIn 2005 concentration ofCO 2 exceeded by far thenatural range over the last650,000 yearsChanges in CO 2 from ice core and modern dataCarbon Dioxide (ppm)350300350stress to societies where stresses already exist. In such cases,marginal impacts could in a sense be the last straw that breaksthe camel’s back.These societies, which are poor and afflicted by several otherstresses, would therefore now most likely face an additionalset of stresses induced by climate change, and we need to beparticularly concerned by this. As Gandhi once said, in decisionsrelated to development, you must look at the impact on‘the last man’, the most underprivileged. In the set of policieswe are discussing for combating climate change, we need tohave a specific and focused concern on the poorest communitiesin the world who will obviously face the worst impacts ofclimate change. Food and security and loss of livelihood wouldof course also be exacerbated by the loss of cultivated landand the effects on sea areas for fisheries, as well as inundation1800 1900 2000Year40035030010000 5000 0Time (before 2005)14.614.414.214.0°C13.813.613.413.210Radiative Forcing (Wm -2 )Source: IPCCSource: IPCC267