If you read or listen to almost any article about climate change, it’s likely the story refers in some way to the “2 degrees Celsius limit.” The story often mentions greatly increased risks if the climate exceeds 2°C and even “catastrophic” impacts to our world if we warm more than the target.

Recently a series of scientific papers have come out and stated that we have a 5 percent chance of limiting warming to 2°C, and only one chance in a hundred of keeping man-made global warming to 1.5°C, the aspirational goal of the 2015 Paris United Nations Framework Convention on Climate Change conference. Additionally, recent research shows that we may have already locked in 1.5°C of warming even if we magically reduced our carbon footprint to zero today.

And there’s an additional wrinkle: What is the correct baseline we should use? The Intergovernmental Panel on Climate Change (IPCC) frequently references temperature increases relative to the second half of the 19th century, but the Paris Agreement states the temperature increases should be measured from “preindustrial” levels, or before 1850. Scientists have shown such a baseline effectively pushes us another 0.2°C closer to the upper limits.

That’s a lot of numbers and data – so much that it could make even the most climate-literate head spin. How did the climate, and climate policy community, come to agree that 2°C is the safe limit? What does it mean? And if we can’t meet that target, should we even try and limit climate change?

Fear of ‘tipping points’

The academic literaturepopular press and blog sites have all traced out the history of the 2°C limit. Its origin stems not from the climate science community, but from a Yale economist, William Nordhaus.

In his 1975 paper “Can We Control Carbon Dioxide?,” Nordhaus, “thinks out loud” as to what a reasonable limit on CO2 might be. He believed it would be reasonable to keep climatic variations within the “normal range of climatic variation.” He also asserted that science alone cannot set a limit; importantly, it must account for both society’s values and available technologies. He concluded that a reasonable upper limit would be the temperature increase one would observe from a doubling of preindustrial CO2 levels, which he believed equated to a temperature increase of about 2°C.

Nordaus himself stressed how “deeply unsatisfactory” this thought process was. It’s ironic that a back-of-the-envelope, rough guess ultimately became a cornerstone of international climate policy.

The climate science community subsequently attempted to quantify the impacts and recommend limits to climate change, as seen in the 1990 report issued by the Stockholm Environmental Institute. This report argued that limiting climate change to 1°C would be the safest option but recognized even then that 1°C was probably unrealistic, so 2°C would be the next best limit.

During the late 1990s and early 21st century, there was increasing concern that the climate system might encounter catastrophic and nonlinear changes, popularized by Malcolm Gladwell’s “Tipping Points” book. For example, continued carbon emissions could lead to a shutdown of the large ocean circulation systems or massive permafrost melting.

It’s all about risk: Chart from 2014 IPCC report shows how higher temperatures lead to higher risk of problems. UN IPCCCC BY-NC

This fear of abrupt climate change also drove the political acceptance of a defined temperature limit. The 2°C limit moved into the policy and political world when it was adopted by the European Union’s Council of Ministers in 1996, the G8 in 2008 and the UN in 2010. In 2015 in Paris, negotiators adopted 2°C as the upper limit, with a desire to limit warming to 1.5°C.

This short history makes it clear that the goal evolved from the qualitative but reasonable desire to keep changes to the climate within certain bounds: namely, within what the world had experienced in the relatively recent geological past to avoid catastrophically disrupting both human civilization and natural ecosystems.

Climate scientists subsequently began supporting the idea of a limit of 1°C or 2°C starting over three decades ago. They showed the likely risks increase with temperatures over 1°C, and those risks grow substantially with additional warming.

And if we miss the target?

Perhaps the most powerful aspect about the 2°C threshold is not its scientific veracity, but its simplicity as an organizing principle.

The climate system is vast and has more dynamics, parameters and variations in space and time than is possible to quickly and simply convey. What the 2°C threshold lacks in nuance and depth, it more than makes up as a goal that is understandable, measurable and may still be achievable, although our actions will need to change quickly. Goals and goal-setting are very powerful instruments in effecting change.

While the 2°C threshold is a blunt instrument that has many faults, similar to attempting to judge a quarterback’s value to his team solely by his rating, its ability to rally 195 countries to sign an agreement should not be discounted.

The 2°C threshold is a lot like trying to stop a truck going downhill: The quicker you hit the brakes (on emissions), the easier it will to lower the risk of problems later. Bruno VanbesienCC BY-NC

Ultimately, what should we do if we cannot make the 1.5°C or 2°C limit? The most current IPCC report shows the risks, parsed by continent, of a 2°C world, and how they are part of a continuum of risk extending from today’s climate to a 4°C.

Most of these risks are assessed by the IPCC to increase in steady fashion. That is, for most aspects of climate impacts we do not “fall off a cliff” at 2°C, although considerable damage to coral reefs and even agriculture may increase significantly around this threshold.

Like any goal, the 2°C limit should be ambitious but achievable. However, if it is not met, we should do everything we can to meet a 2¼°C or 2.5°C goal.

These goals can be compared to the speed limits for trucks we see on a mountain descent. The speed limit (say 30 mph) will allow trucks of any type to descend with a safety margin to spare. We know that coming down the hill at 70 mph likely results in a crash at the bottom.

In between those two numbers? The risk increases – and that’s where we are with climate change. If we can’t come down the hill at 30 mph, let’s try for 35 or 40 mph. Because we know that at 70 mph – or business as usual – we will have a very bad outcome, and nobody wants that.

Acting on climate change is Africa’s opportunity Continent is well placed to reap benefits in investment and jobs beyondbrics Read next An Inconvenient Sequel: Truth to Power — a gift for making statistics enthral Part of a wind farm outside Nairobi, Kenya. The country is building Africa’s biggest wind farm, creating 2,000 jobs © AFP Share on Twitter (opens new window) Share on Facebook (opens new window) Share on LinkedIn (opens new window) 3 Save to myFT JULY 25, 2017 by: Ngozi Okonjo-Iweala Acting on the climate remains firmly on the global agenda. It remained a top priority for all but one of the G20 leaders who gathered in Germany this month. That is because it is increasingly clear that strong action is in the economic self-interest of countries at all stages of development.

Climate investment opportunities in emerging markets could be as much as $23tn by 2030. National governments, states, cities and businesses are all seeing the opportunities of climate action, from employment to investment and from smarter growth to a cleaner, healthier future for all.

Take jobs, where climate action could generate a veritable bounty of clean energy employment. Globally, 62 per cent of renewable energy jobs are already in Asia, with 3.6m jobs in China alone, according to the International Renewable Energy Agency. China expects to create 13m jobs in the renewable energy sector over the next four years. Across the African continent, forays into the clean energy industry have been promising, with renewables already providing 62,000 jobs and much potential ahead. beyondbrics Emerging markets guest forum beyondbrics is a forum on emerging markets for contributors from the worlds of business, finance, politics, academia and the third sector.

All views expressed are those of the author(s) and should not be taken as reflecting the views of the Financial Times. Algeria, for example, created 3,500 jobs in the construction of 14 grid-connected solar PV projects in 2015, with 700 permanent jobs expected in operation and management. Kenya is building Africa’s largest wind farm at Lake Turkana, planned to be fully operational later this year. Its construction has created more than 2,000 local jobs since October 2014. Overall investment in sub-Saharan Africa, particularly for clean energy, represents a $783bn opportunity.

We are also particularly well placed to take advantage of cheap and plentiful resources from the sun and wind. The potential for renewables in sub-Saharan Africa stands at about 1,100 gigawatts of solar capacity, 350 gigawatts of hydropower and 109 gigawatts of wind. This would be more than enough to meet future demand. Meanwhile, the cost of utility-scale solar in Africa fell 50 per cent from 2010 to 2014 and continues to fall. Further upstream, African countries could also capitalise on opportunities to get more involved in the production of low-carbon technology. Rather than importing solar panels and wind turbines from elsewhere, Africa can establish itself as a green manufacturing giant. We shouldn’t let people just sell us items that we are well positioned to produce ourselves.

Instead, we can lead in developing and producing the clean energy solutions we need. African cities can leapfrog the urban development challenges that other fast moving economies have faced. The population of Lagos, for instance, is set to reach 25m people by 2030. The city’s traffic congestion is already notorious, costing commuters 3bn hours a year from 2007 to 2009 and — in one memorable case — costing a man his marriage. But recent investment in bus-oriented transport infrastructure, with dedicated lanes for environmentally friendly mass-transit vehicles, has improved the situation considerably and at a fraction of what it has cost elsewhere.

Getting our cities right and, in some cases, building them right in the first place will not only deliver economic benefits but will help us avoid the costs of sprawl, traffic congestion and debilitating air pollution that plague residents of Beijing or Delhi. Rural economies matter just as much as our urban opportunities. And here too, positive actions are yielding solid results. Farmers in Niger, for example, using new agroforestry techniques benefited from increased grain production as well as increased gross annual income, going up by $1,000 per household for more than 1m households. Local communities in northern Ethiopia organised themselves to control livestock grazing and wood cutting on degraded plateaux and mountain slopes, allowing vegetation to regenerate naturally and making the region greener than it has been for well over a century.

Large-scale initiatives are also delivering. AFR100, for instance, was launched in 2015 to bring 100m hectares of deforested and degraded landscapes across Africa into restoration by 2030. Within a year, 21 countries have signed on to committing 63.5m ha into restoration and more than $1bn in development finance and $545m in private investment have been secured. There should be no doubt — in developing countries the world over and especially in Africa — that the new climate economy of the future will bring benefits ranging from jobs in clean energy to improved air quality and more productive land. Staying the course will put us at the forefront of this green economic revolution. That’s a good place to be. Ngozi Okonjo-Iweala is co-chair of the Global Commission on the Economy and Climate and chair of the Global Alliance for Vaccines and Immunization. She was previously finance minister of Nigeria and managing director of the World Bank

Global Water Shortage Risk Is Worse Than Scientists Thought

About two-thirds of the world’s population faces water scarcity for at least one month during the year.

Sheep seen on Manie van Rooys farm on November 6, 2015 near Frankfort, South Africa. Free State farmers have been severely affected by what is considered as the worst drought since 1992.

The growing risk of worldwide water shortages is worse than scientists previously thought, according to a new study.

About 66 percent, which is 4 billion people, of the world’s population lives without sufficient access to fresh water for at least one month of the year, according to a new paper published Friday in the journal Science Advances.

Previous studies calculated a lower number, estimating that between 1.7 and 3.1 billion people lived with moderate to severe water scarcity for at least a month out of the year.

Scientists, led by Dr. Arjen Hoekstra of the Netherlands’ University of Twente, used a computer model that is both more precise and comprehensive than previous studies have used to analyze how widespread water scarcity is across the globe. Their model considers multiple variables including: climate records, population density, irrigation and industry.

“Up to now, this type of research concentrated solely on the scarcity of water on an annual basis, and had only been carried out in the largest river basins,” Hoekstra said in a statement. “That paints a more rosy and misleading picture, because water scarcity occurs during the dry period of the year.”

“The fact that the scarcity of water is being regarded as a global problem is confirmed by our research,” Hoekstra added. “For some time now, the World Economic Forum has placed the world water crisis in the top three of global problems, alongside climate change and terrorism.”

About two-thirds of the world’s population faces water scarcity for at least one month out of the year.

Severe water scarcity happens when consumption is twice as high as available resources, according to the study’s researchers. Consequently, half of those suffering from water scarcity are in the world’s two most populous countries — India and China — where demand is high.

High-scarcity levels are also widespread in areas with significant irrigated agriculture (like the Great Plains in the United States) or low natural availability of fresh water (like the Arabian Desert) where populations are also relatively dense, according to the study. Similar patterns exist in the south and western United States where heavily populated states like California have been in a drought for years. 

The consequences of water scarcity can result in economic losses due to crop failure, limited food availability and poor business viability, and can threaten environmental biodiversity. When faced with scarcity, areas in need of water often resort to pumping groundwater, which can permanently deplete the supply.

Water shortages have also precipitated or heightened the potential for global conflicts in places like the Middle East and Africa.

Freshwater scarcity is a major risk to the global economy, affecting four billion people directly,” Hoekstra told The New York Times. “But since the remaining people in the world receive part of their food from the affected areas, it involves us all.”

Despite the grim findings, the study recommends ways to reduce scarcity, such as increasing reliance on rain-fed rather than irrigated agriculture, improving the efficiency of water usage and — perhaps the most challenging for humans — sharing what’s available. The researchers point out that for these solutions to be effective, governments, corporations and investors will need to cooperate.

How To Feed the World After Climate Change

There are limits to how technology can help post-climate change agriculture.

Photograph courtesy San Luis Obispo County, Calif., Department of Agriculture

On Thursday, April 12, Future Tense, a partnership of Slate, the New America Foundation, and Arizona State, will host a live event in Washington, D.C., on the future of food. “Feeding the World While the Earth Cooks” will examine post-climate-change agriculture, the rising demand for meat, and more. Click here for a full agenda and to RSVP.

When my daughter turned 7 last week, we celebrated with a homemade chocolate cake. I wonder whether she’ll be able to do that with her own child someday. Scientists are already warning that chocolate and wheat (the raw material for flour) will become harder to grow as temperature and rainfall patterns are disrupted.

Over the next 50 years, climate change will transform the world in ways we have only begun to imagine. Humans have changed the weather on this planet, and that will change everything, especially how we grow food.

Consider corn. The major crop (by volume) grown in the United States, corn does not reproduce at temperatures higher than 95 degrees. During the 20thcentury, Iowa experienced three straight days of 95 only once a decade. But by 2040, if greenhouse gas emissions remain on their current high trajectory, Iowa will experience three straight days of 95-degree heat in three summers out of four, professors Katharine Hayhoe of Texas Tech University and Donald Wuebbles of the University of Illinois have calculated.

John Beddington, the chief science adviser to the British government, has warned that by 2030 the interlocking trends of climate change, population growth, and resource scarcity may result in “major destabilization,” including street riots and mass migrations as people flee shortages of food and water.

But that nightmare scenario need not come to pass. We already know what works—and what doesn’t—to feed a post-climate-change world. In fact, many of the practices and technologies we need are already in use, in the United States and abroad.

What’s needed is to bring these isolated success stories to scale, to make them the rule rather than the exception. But that’s not an easy task when the agricultural approaches that actually improve people’s lives can be overshadowed by inferior alternatives propped up by large PR budgets or government support.

Take the argument that more heat- and drought-resistant seeds are what’s needed to cope with climate change. The good people at Monsanto have spent lots of advertising money to spread this message.  And joined by two other high-profile backers of genetically modified organisms—the Bill and Melinda Gates Foundation and the Warren Buffet Foundation—Monsanto has claimed to have already increased corn yields in Africa by 25 percent to 35 percent. There’s a catch, though: The only documentation for those results was found on Monsanto’s own website and was later removed.

Most peer-reviewed research has found little reason for optimism that GMO seeds will revolutionize yields in the face of climate change. The most authoritative analysis is found in Agriculture at a Crossroads, the landmark report issued by the International Assessment of Agricultural Knowledge, Science and Technology for Development in 2009. Testifying before Congress, Robert Watson, the scientist who directed the assessment, explained in the gentlest possible terms that GMO crops are an unproven technology whose benefits remain highly uncertain: “[I]t is likely to be several years at least before these [GMO] traits might reach possible commercial application [my emphasis].”

So better seeds alone won’t save us. Instead, feeding the world under climate change will require a broader strategy, grounded in two imperatives. On the one hand, we must rapidly reduce the amount of greenhouse gases in the atmosphere, to avoid facing unmanageable amounts of future climate change. On the other, we must prepare our agricultural sectors for the climate impacts already “in the pipeline,” which will be severe enough.

The currently dominant system of industrial agriculture is a loser on both fronts. It emits enormous amounts of greenhouse gases, partly because it consumes huge quantities of oil—to power farm equipment, manufacture fertilizer, and ship food through global networks. Meanwhile, its preference for monoculture rather than diversity makes it extremely vulnerable to hot and volatile weather, as well as to the uptick in pests and diseases such weather will bring.

“We absolutely have to develop seeds for improved and climate-adapted varieties, but we also need to increase the diversity of seeds,” says Sara Scherr, the president of Ecoagriculture Partners, an NGO in Washington, D.C. (Scherr will also be speaking at the upcoming Future Tense event “Feeding the World While the Earth Cooks.’) “A lot of the focus is on, ‘Let’s get a few seeds that are drought-resistant that can be used on millions of hectares.’ The current business model in agriculture is based on maximizing volume, which militates against diversity.”

More and more agricultural experts are saying we need a shift to ecological agriculture, sometimes known as agro-ecology. Ecological agriculture eschews applying chemical fertilizers to soil; rather, it favors compost and manure, which increase the soil’s fertility and ability to retain water—key advantages against hot, dry weather. And rather than monocultures, agro-ecology fosters a diverse agricultural landscape where nature’s processes are utilized not only to grow food but to maintain the health of the soil, water, and biodiversity that make agriculture possible in the first place.

In western Africa, for example, thousands of the poorest farmers on earth are capturing scarce rainfall and rejuvenating soil fertility by growing trees amid their fields of millet and sorghum. Despite enduring some of the hottest, driest weather on earth, these farmers have returned greenery to 12.5 million acres of land—enough to see from outer space, courtesy of satellite imagery from the U.S. Geological Survey. More important, underground water tables have been replenished, and crop yields have doubled and tripled.

Mixing forests and farmland is also being explored in China, where Lin Erda, a senior government scientist, has joined with Greenpeace to endorse ecological agriculture as the best way to cope with climate change. Raising ducks and fish in rice paddies, for example, reduces both greenhouse gas emissions and the need for chemical fertilizers; the fish decrease the methane that the paddies would otherwise emit, while the ducks control pests.

But how does ecological agriculture compare against industrial agriculture’s greatest strength—its ability to produce prodigious amounts of food? That’s a vital question on a planet where, even today, one in seven people goes hungry.

In Africa, extensive field studies show ecological agriculture matching the yields of conventional agriculture, while also boosting water supply and soil fertility. But Africa is a special case. Bypassed by the Green Revolution of the 1970s, it never got used to the inflated yields that industrial agriculture made possible.

In the United States and Europe, switching from industrial to ecological agriculture has invariably caused an initial decline in yields. However, after a brief transition period of three to five years, ecological agriculture’s yields rebound to equal those of industrial agriculture, according to a 30-year studyconducted by the Rodale Institute.

And ecological agriculture’s advantages promise to be even greater under climate change.  In drought years, Rodale found, its yields were 31 percent higher than conventional yields. Ecological agriculture also built rather than depleted soil fertility while recharging groundwater supplies. Finally, it produced 40 percent fewer greenhouse gases than industrial agriculture.

My daughter was born into what I call Generation Hot—the 2 billion young people worldwide who will spend the rest of their lifetimes coping with the hottest, most volatile climate human civilization has ever known. Agriculture, it turns out, is one of the few tricks humanity still has up its sleeve to avoid the unmanageable and manage the unavoidable of climate change. Let’s not squander it.