The publication of the Intergovernmental Panel on Climate Change’s Fifth Assessment Report has drawn renewed attention to the threat of global warming, writes David Tresilian

The publication on 13 April of the third in a series of reports by working groups of the Intergovernmental Panel on Climate Change (IPCC) will have done little to assuage the anxieties of those concerned about the problem of global warming.

The report, which together with those of the other two working groups makes up most of the IPCC’s Fifth Assessment Report on Climate Change, concludes that global emissions of greenhouse gases have risen to unprecedented levels despite policies intended to reduce them.

In order to have a likely chance of limiting the global mean temperature increase attendant on climate change to two degrees Celsius, considered to be the safe upper limit, global greenhouse gas emissions will have to be reduced by 40 to 70 per cent compared with 2010 by 2050 and to near zero by 2100.

Even less ambitious temperature goals, projecting a mean temperature increase of above two degrees Celsius and thus courting the risk of climatic catastrophe, will require ambitious emissions reductions, the report says. There may even be a need to develop technologies to remove carbon dioxide from the atmosphere directly in addition to reducing emissions.

According to Ottmar Edenhofer, the group’s lead author, speaking in Berlin during the release of the working group report, “climate policies in line with the two degrees Celsius goal need to aim for substantial emission reductions. There is a clear message from science: to avoid dangerous interference with the climate system [thought to kick in above the two degrees Celsius goal], we need to move away from business as usual.”

For the time being, there is little sign that this is happening, with the report noting that emissions grew more quickly between 2000 and 2010 than in each of the previous three decades. This is very far indeed from the IPCC recommendation of reducing emissions by up to 70 per cent by 2050 in order to keep temperature rises within safe limits.

At a time when humanity finds itself like a lobster caught in a saucepan as the heat below it rises, it is important to be clear about the consequences, according to the best scientific projections, of taking inadequate measures to control climate change or, worse, simply continuing with business as usual.

For Egypt, these consequences could include reduced crop yields leading to increasing pressures on food security, water stresses and drought as mean precipitation and Nile discharge fall, and threats to coastal populations as a result of sea-level rises and low-lying agriculture disappearing as a result of salination or inundation.

Mitigation and adaptation: Current thinking on climate change has concentrated on mitigation – actions taken to reduce the amount of greenhouse gases pumped into the atmosphere and thus the severity of temperature rises – and adaptation – actions taken to prepare for what are probably its inevitable effects.

Mitigation efforts commonly include reductions in greenhouse gas emissions from energy production, transport, buildings, industry, land use and human settlements, among them moving to low-carbon energy technologies and either halting deforestation or planting forests.

Adaptation efforts include planning for the climatic changes that are likely to take place even if a two degree Celsius rise in mean temperatures is achieved, among them building coastal or river defences, shifting populations and planning for more efficient water and energy use.

According to Nicholas Stern, author of the UK’s Stern Review on the Economics of Climate Change (2007), one of the first attempts to cost mitigation and adaptation efforts for a major industrialised economy in a systematic way, keeping atmospheric carbon dioxide concentrations at or below 500 parts per million (ppm), compared to their mid-nineteenth century level of around 285 ppm, and thus reducing the risk of anything above a two to three degrees Celsius rise in global temperatures, will still require enormous efforts in reducing emissions.

Writing in 2009, Stern had already abandoned the aim of keeping atmospheric concentrations below 450 ppm, hoped for by the IPCC authors, on the grounds that “we are already at 430 ppm.” Limiting temperature increases, he wrote, with high probability to two degrees Celsius, “which is often advocated on the grounds that anything higher would be dangerous, is a goal that is unlikely to be achievable, unless we discover and implement ways of extracting greenhouse gases from the atmosphere on a large scale.”

“At 500 ppm, the chances of exceeding two degrees Celsius are over 95 per cent, but we would still have a strong chance [calculated at 56 per cent] of staying below three degrees Celsius.” Continuing with business as usual would likely lead to an at least 750 ppm concentration level by the end of this century, translating into a 50 per cent likelihood of temperature rises of five degrees Celsius. Rises on this scale would be “devastating,” Stern writes, not seen since the Eocene period 30 to 50 million years ago when the world’s reduced landmass largely consisted of swampy forest.

“With a temperature increase of two to three degrees Celsius,” projected under even optimistic scenarios, “many parts of the world will experience severe dislocation, with rising sea levels, a greater frequency of intense storms and hurricanes, the melting of glaciers and snows which will lead to torrents and flooding in wet seasons, droughts in many parts of the world, and a high risk that the major rainforests will collapse.”

Somehow emissions will have to be reduced, according to the IPCC authors by up to 70 per cent by 2050 in order to stand a good chance of meeting a two degrees Celsius limit. And even if the two degrees limit is met, implying keeping atmospheric concentrations of carbon dioxide well below the 500 ppm limit, adaptation efforts will have to be put in place that would likely include infrastructure that is more resilient to a changing climate, better water management and significant changes to urban planning and population distribution.

Writing what he called a “global deal” for coping with climate change, Stern commented in 2009 that “the next forty or fifty years of climate change are shaped by what we have already done and what we will do over the next decade or two.” However, while climate change is a problem that faces the world as a whole, it is one that does so unequally. Not only does responsibility for climate change lie with those who have historically been the greatest emitters of greenhouse gases, in other words industrialised Western nations, but the effects of it will be felt disproportionately by poorer countries.

“Developing countries feel a powerful and understandable sense of injustice,” Stern writes. “They were not responsible for the majority of greenhouse gases. But they will be hit earliest and hardest. And now they are being told to follow a path to prosperity very different from that followed by rich countries, a path for which some argue there is as yet no model” as it involves massive reductions in the burning of fossil fuels.

Some of the impacts on developing countries that the world is already seeing include the flooding of low-lying island states and low-lying areas, increasing droughts and water stresses across Africa, and the retreat of the Himalayan glaciers, threatening water shortages downstream and much of Indian agriculture. These are likely to increase over coming decades.

Impacts on Egypt: In Egypt, the consequences of climate change could include reduced crop yields leading to increasing pressures on food security, water stresses and drought as mean precipitation and Nile discharge falls, and threats to coastal populations due to sea-level rises and low-lying agriculture disappearing or losing yield as a result of salination or inundation.

Various attempts have been made in recent years to quantify the possible effects of climate change on Egypt, with various scenarios agreeing that the country faces serious risks as a result of its geographical situation, its population distribution, and its reliance on Nile River water. According to a 2013 report by the United Nations Development Programme (UNDP) in association with the Egyptian government and various other UN agencies, agricultural production could decrease by eight to 47 per cent by 2060, with employment losses of up to 39 per cent, as a result of losses of agricultural land and temperature rises.

The report, entitled Potential Impacts of Climate Change on the Egyptian Economy, estimates that “hundreds of billions of Egyptian pounds, about two to six per cent of future gross domestic product (GDP), could be lost from effects on water resources, agriculture, coastal resources and tourism.” Thousands could die from increased air pollution and heat stress, and millions could lose their homes in low-lying areas of the Delta due to sea-level rises or their jobs in agriculture as a result of climate change.

“The value of property in the Nile River Delta threatened by sea-level rises could be seven to 16 billion EGP,” the report says. “Higher temperatures could reduce annual tourism revenues by 90 to 110 billion EGP,” it adds, with areas of the country becoming too hot for tourists to visit.

With regard to water resources and agricultural production, the report says that in a country where 88 per cent of water needs are provided for by Nile water and where agriculture is mostly supported by irrigation, any reduction in Nile River flows as a result of climate change can be expected to place additional stresses on water resources and negatively impact agricultural production. The average projection for reduced Nile River flows in the examined studies was of about 10 per cent by 2060, though some models gave figures of more than 33 per cent, the report says.

Higher average temperatures, likely under climate change, will translate into lower yields for staple crops and greater irrigation needs. “When Nile flow decreases 12 per cent, production drops by more than one-quarter; when flow decreases by one-third, production is cut in half,” the report comments, translating into greater agricultural unemployment and, without massive increases in food imports (up to five times current levels), large increases in food prices.

As if these projections were not sobering enough, the impact of sea-level rises on Egypt’s low-lying coastal areas, notably in the Nile Delta, will likely also have large economic impacts. Most of the agricultural land directly threatened by sea-level rises as a result of climate change is in the north-east Nile Delta, where one-fifth of the land risks inundation by 2060. However, it is not only agricultural land that is at risk from sea-level rises since Alexandria, in the north-west Delta, and Port Said, in the north-east, are also at risk of significant subsidence or inundation.

Depending on whether pessimistic or optimistic scenarios are selected as the basis of projected estimates, “a quarter of a million to one million housing units would be at risk of sea-level rises” by 2060, even assuming a halt to current construction. This translates into an annual loss of property values of seven to 16 billion EGP by the same date, along with considerable changes in the distribution of urban populations.

The economic impacts of climate change, the report suggests, are likely to include “reduced crop yields, less water, a significant reduction in agricultural production, either losses of property or higher coastal protection costs, higher mortality from air pollution, and a loss in tourism revenues,” all quantifiable according to pessimistic or optimistic scenarios.

“Malnutrition and unemployment would increase and total economic losses by 2060 could be several hundred billion EGP per year. These estimates do not account for potential adverse impacts of higher temperatures and lower flow on fisheries, hydropower and transportation. Other ecosystems besides coral reefs [damaged by rising water temperatures and acidification as a result of climate change] could be harmed, water quality could deteriorate, and there could be other risks to human health besides reduced air quality” and the effects of heatwaves and generally rising temperatures.

An earlier report, Climate Observations, Projections and Impacts: Egypt, commissioned in 2011 from the UK Meteorological Office, a UK government agency, agrees with the UNDP report’s main findings and headline numbers. According to this report, climate change is likely to lead to a three to 3.5 degrees Celsius mean increase in temperature in Egypt by 2100 over the 1960-1990 baseline climate (the two degrees Celsius projection is for mean global temperatures), with summer temperatures, already peaking during recent heatwaves, becoming increasingly uncomfortable.

Yield deficits are likely for wheat, rice and maize production as a result of climate change, the report says, and Nile River discharge could decline substantially, threatening food security and adding to water stresses. Moreover, in a study looking at the impact of a one metre sea-level rise as a result of climate change on 84 developing countries, “Egypt was ranked the second highest with respect to the coastal population affected, third highest for the coastal GDP affected, and fifth highest for the proportion of urban areas affected.”

Adaptation efforts: Even if mitigation efforts succeed in keeping global temperature rises to within the mean two degrees Celsius target, climate change will have serious effects on Egypt, and preparation for these needs to start through adaptation efforts.

According to Stern, such efforts, targeted on the specific vulnerabilities of the countries concerned, should be part of a “global deal” on climate change since while the effects of the latter are likely to be felt at least at first disproportionately by developing countries, responsibility for rising global temperatures can be laid at the door of the developed countries. “An effective response to the global challenge of climate change requires international collaboration on a scale which is unprecedented,” he writes.

“It will be the farmer, the firm and the local community [in the developing countries] that will have to adjust techniques, crops, irrigation, buildings, transport, flood control and other forms of infrastructure” to meet the challenges of climate change. All this will cost considerable sums, and these sums are “relevant to a world that should recognise some collective responsibility, both for international development and for the difficulties caused by climate change.”

But even if the world does not recognise such a collective responsibility and does not assist developing countries in making the necessary adaptation efforts, as at present unfortunately seems to be the case, such efforts will nevertheless have to begin. In the Egyptian case, they will include changes to water resources, agriculture, health and coastal defences.

Writing on the kinds of adaptation efforts needed if Egypt is to manage the effects of climate change and minimise their economic impacts, the authors of the UNDP report write that water resources should be adapted by finding ways to increase efficiency and reduce consumption and by developing new water sources through desalination and reuse. In agriculture, more efficient use of water resources should also be attempted and heat-resistant and salinity-resistant crop varieties should be introduced in an attempt to narrow reductions in yields and maintain agricultural output.

In order to protect coastal areas from sea-level rises of one metre or more by 2100 (the UNDP authors say planning for a two-metre rise “may be prudent”), coastal protections should be reinforced or built and wetlands created in vulnerable areas to act as buffers to storm surges. However, as in other areas of adaptation to climate change, cost-benefit analysis is in order. Would it make more sense simply to abandon areas of vulnerable coastal land given the expense and possible futility of trying to protect them?

Key choices facing Egyptian policy-makers are likely to include “whether to protect such areas from sea-level rises, accommodate sea-level rises [perhaps by turning such areas over to coastal wetlands], or move settlements or other activities further inland.” The latter choice would probably cause the greatest disruption, and it would lead to major changes to the distribution of population. Moreover, as the authors write, a projected loss of millions of jobs in agriculture is already likely to lead to increased rural-to-urban migration.

Air and water pollution will need to be more vigourously monitored and controlled, these being even today considerable health concerns, and heatwave and disease-surveillance systems will need to be established or reinforced. “Egypt already has tremendous problems with air quality,” the UNDP authors note, with some 20,000 people dying every year as a result of high air pollution and poor air quality costing the country one to three per cent of GDP. Adaptation to climate change will need to find ways of reducing air and water pollution, enhancing disease surveillance, and improving the country’s public health system.

Narrowing options? Commenting on the IPCC’s latest working group report on 19 April, the UK magazine The Economist summarised the group’s findings. Should present trends continue, it will be impossible to meet the two degrees Celsius mean temperature target, the magazine said. But if temperature rises reach four or five degrees by 2100, as seems likely should these trends continue, the results will be “catastrophic.”

However, the magazine rubbished the IPCC’s recommendations, describing its calculations of the cost of mitigating and adapting to climate change as “preposterous” and “next to useless.” “Germany and Spain have gone further than most in using public subsidies to boost the share of renewable energy” in efforts to reduce greenhouse gas emissions, “and their bills have been enormous.”

While the article does not say so directly, the implication seems to be that whatever Germany, Spain and other countries have spent up to now is out of proportion to the expected benefits of avoiding climatic catastrophe 80 years hence. However, writing in 2009 Stern was prepared to argue that “extra costs for the vast majority of industries… in the order of one to two per cent of global GDP per annum over the period to 2050” should be accommodated, especially if such sacrifices, felt by present generations, could save the planet from catastrophe.

How much is it reasonable to spend today to avoid disaster tomorrow? For The Economist, 0.6 per cent of GDP per year (the current cost of emissions-reduction measures in Germany) seems to be too much. For Stern, a figure three or four times that amount should be envisaged if we are even minimally serious about saving the planet.

“There is no doubt that moving to a low-carbon growth path will involve real economic and political costs.” Given the stakes involved, “the costs must be acknowledged and managed and not dismissed.”