Innholdsfortegnelse for EG08 i New Scientist - The Essential Guides

CLIMATE CHANGE is the greatest challenge of our age – perhaps of any age, measured by the size of societal change needed to mitigate it and adapt to it. We stand now at a critical juncture. As this latest New Scientist Essential Guide is published, an intense diplomatic effort is under way ahead of the crucial UN-backed COP26 climate summit in Glasgow, UK, in November 2021. At stake is a credible plan to deliver the goal agreed in Paris in 2015, to limit global warming to a nominally safe 1.5˚C by reducing greenhouse gas emissions to “net zero” by mid-century. There is no better time to be informed about what’s at stake – about the basic science of climate change, the history of efforts to combat it, the effects of…

Around 50 million years ago in the early Eocene, 15 million years after the dinosaurs went extinct, Earth was sweltering. Average temperatures were 14°C above pre-industrial levels. There was no permanent ice anywhere on the planet and sea levels were more than 70 metres higher than today. The cause of this extended heatwave appears to have been a massive injection of greenhouse gases into the atmosphere. The source remains unclear – volcanic eruptions and comet impacts have been proposed – but whatever caused it, carbon dioxide levels peaked at about 1400 parts per million (ppm), compared with around 420 ppm today and 280 ppm in pre-industrial times. From that high point, Earth gradually cooled, as slow-moving geological processes scrubbed CO2 out of the atmosphere. One key factor was mountain building.…

IT WAS an astounding temperature recorded in Lytton in British Columbia on 29 June 2021, shortly before the village was consumed by a wildfire. The mercury hit 49.6°C, a record for Canada, and the world’s highest temperature ever recorded north of 45°N. Such records are falling wherever you are in the globe. In Australia, January 2017 was the hottest ever recorded in Sydney and Brisbane, and great swathes of the south-east endured temperatures that often exceeded 40°C for weeks on end. In January 2018, the temperature in Sydney briefly climbed to over 47°C. Climate models see both it and Melbourne experiencing heatwaves with highs of 50°C by 2040. “Going out to 40 or 50 years, basically [such summers] will be normal,” says Sarah Perkins-Kirkpatrick at the Climate Change Research Centre…

FOR biodiversity, climate change is, in military jargon, a threat multiplier. Global warming is having an impact on species and ecosystems that in many cases are already under strain from pollution, or through carving up their habitat for farmland and roads. The effects of the warming we are experiencing now are already in some cases dramatic. In the Arctic, the loss of more and more sea ice each summer is affecting many animals, from walruses to polar bears. Polar inhabitants have nowhere colder to go, but many creatures elsewhere are already moving to stay in their comfort zone. Marine species, including mammals, birds, fish and plankton, have shifted their ranges by hundreds of kilometres. Other effects are more subtle. Oceanic low-oxygen zones are expanding because oxygen is less soluble in…

A central plank of plans to combat climate change is the principle that greenhouse gas emissions should be paid for. Governments can implement this in several different ways, from direct carbon taxes – in which governments put an explicit price on the right to emit greenhouse gases – to “shadow pricing” in the form of regulations that discourage carbon-intensive industry. Most countries already have a piecemeal carbon tax, in the form of special levies on petrol, for example. The main aim here is generally to raise revenue. In contrast, some schemes afoot now, for example in the European Union and Canada, plan to impose a flat tax per tonne of carbon dioxide or equivalent, with the aim of nudging entire economies away from polluting activities. As economies adjust, the carbon…

IN 2015, 12 leading environmental institutions from around the world, led by Finland’s national innovation fund, SITRA, set out to assess the potential of emissions-reducing innovations. “At the start of the project, we had a very simple question in mind,” says SITRA’s Outi Haanperä. “How far could we go just using and scaling up existing technologies?” Quite a way. The assessment identified 18 solutions that, rolled out as widely as possible, would cut global emissions by about 12 gigatonnes of carbon dioxide annually by 2030, or 25 per cent of projected emissions if countries stick to their commitments under the 2015 Paris climate change deal. Implementing them would cost $94 billion a year, less than a fifth of what governments currently shell out in direct fossil-fuel subsidies. Add in the…

THE covid-19 pandemic has been a reminder of how little we want to return to the days when deadly infections carried away most of us. Success against infectious disease in the past century or so, alongside other improvements in health, sanitation and nutrition, have dramatically improved human survival rates. In 1860, the figure for child mortality worldwide was more than 40 per cent. Today, it is around 4 per cent, and a fraction of a per cent in high-income economies. In western Europe, life expectancy is now about 80. In sub-Saharan Africa, it is over 60, up from 44 half a century ago. This change in death rates marks the first stage in the “demographic transition”: a seismic change in which nations shift over decades from high birth and death…

BY NOW, most reasonable people understand that they have been burning too much carbon. Most of these same people are still burning too much carbon. There is a big gap between our views on climate change and our actions to do something about it. Unfortunately, actions are what matter, not sentiments or good intentions. Most of us have taken some steps in the right direction. However, we continue to produce greenhouse gases. Sometimes, we truly cannot do better. Not everyone can afford to buy solar panels, rural residents cannot commute by subway, and people who live in cold climates cannot go without heating. These are structural barriers, beyond an individual’s control. However, for those not restricted by such barriers, adopting more pro-climate choices and behaviours is quite feasible. Yet, so…

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IT MAKES up just 0.04 per cent of the atmosphere, but carbon dioxide is a small molecule with a big bite. We have known this for more than 150 years. In 1861, John Tyndall discovered that CO2’s three atoms vibrate when hit by certain photons. Photons from the sun pass straight through the atmosphere, unhindered by CO2, but when they reach Earth’s surface they bounce back as infrared photons – or heat, in other words. Instead of passing through the atmosphere, these photons are absorbed by CO2 and released again, only this time they fly off in random directions. More heat stays within the atmosphere than goes back out into space: the greenhouse effect. Other greenhouse gases act in the same way: methane, nitrous oxide, CFCs, ozone and water. But…

IN 1965, a report from US president Lyndon Johnson’s Science Advisory Committee reported rising levels of carbon dioxide in the atmosphere, for which “at least during the recent past, fossil fuel combustion has been the only significant source”. The committee’s environmental pollution panel warned that by 2000 this increase “may be sufficient to produce measurable and perhaps marked changes in climate” that “could be deleterious from the point of view of human beings”. There are many reasons why we haven’t heeded such warnings, not least a concerted campaign of disinformation on behalf of some fossil fuel companies. The first high-profile scientific warning about climate change came in 1988 from James Hansen, then the director of the NASA Goddard Institute for Space Studies, in testimony to the US Congress. That same…

How do you describe your job to people? I’m trying to answer the question of whether, and to what extent, human-caused climate change altered the likelihood and intensity of recent extreme weather events. The data-processing aspect of that is a very small part of my work. Most of my day-to-day work is thinking about the most appropriate data sources to use for these kinds of studies, or which models should be used, or how we can test the models better to see whether they are able to reliably simulate the weather event. Does having more extreme weather events as the planet warms make attribution easier or harder? The main difficulty is in whether we have models that really represent the processes behind extreme weather events. For example, do we have…

The changes to the Earth system from climate change, both present and future, matter because they impact human well-being. Changes at sea and on land will have a significant impact on food security: warming is expected to reduce the productivity of livestock farming, fisheries and aquaculture. Despite hopes that increased warmth and carbon dioxide could make terrestrial crop agriculture more productive, real-world yields, particularly in the tropics, appear to be falling as the climate warms. Faster growth under conditions of higher CO2 will also lead to lower levels of some nutrients in crops. An extra 95,000 children a year are projected to die of malnutrition in a warmer world, and 48,000 more from diarrhoea, according to the World Health Organization. Mosquitoes carrying malaria, dengue fever, chikungunya, yellow fever and Zika…

UNTIL recently, our quest for clean energy was mired in imponderables. Nuclear fission power is expensive and mired in controversy. Nuclear fusion, directly harnessing the kind of reactions that power the sun, remains a distant dream. Meanwhile, renewable energy is too unreliable to meet all our power demands. That last statement is where the running has changed. Clean energy from wind and solar has come on in such leaps and bounds in the past decade or so that an impassioned debate has broken out among energy experts as to whether “100 per cent renewables” is now within our grasp – and, if so, how we get there. “We can really mess this up,” says Dan Kammen at the University of California, Berkeley. “Just because we can make the shift doesn’t…

Since you wrote The Population Bomb, the narrative has moved away from overpopulation being a problem. Should it have done? The main problem we have with all our environmental dilemmas is too much consumption. Humans are just using too much of what there is and using more all the time. But to say that the aggregate consumption is just a problem of overconsumption is like saying that the area of a rectangle is it’s too wide; it has nothing to do with length. The number of people and how much each one consumes multiply together to give you your aggregate consumption. So you stand by your dire predictions? It is not the book I would write today. I would put more emphasis on consumption, particularly because we know we can…

SOURCE: NOAA → Turn to chapter 2 for more on efforts to curb global warming to 1.5°C THE best way to measure global warming would be to look at Earth as a whole: land, sea and atmosphere. But our measurements focus on the thin layer we live in. Mean global surface temperature usually refers to the heat of the air 2 metres above the land surface, or at the sea’s surface. We get an idea of how this temperature is changing from thousands of weather stations on land, and from ships and buoys at sea. Each reading is checked to see whether the temperature is lower or higher than the long-term average for that place at that time of year. They are then combined to work out how the average…

The 1.5°C climate target was picked not because it is the right number, but because it was convenient. A 1990 report concluded that limiting global warming to 1°C would be safer than a 2°C cap. But in 1996, with 1°C already looking out of reach, 2°C was adopted as a target by the European Union’s Council of ministers. This led to its 2010 adoption by the UN. When the Paris climate agreement was being negotiated in 2015, island nations facing watery oblivion demanded a more ambitious target. Since the world was already around 1°C warmer by then, 1.5°C was chosen. But as the IPCC made clear in a report on the 1.5°C target published in 2018, it is not a safe limit. The climate change impacts we are already seeing,…

What do you expect will happen to global carbon dioxide emissions after the pandemic? Over the past decade, emissions had been going up about 1 per cent per year. Our estimates suggest a reduction in emissions [during the 2020 lockdowns] of between 4 and 7 per cent. This is huge. In 2009, during the financial crash, emissions dropped 1.4 per cent. They then grew more than 5 per cent in 2010, which brought us exactly back to where we were like nothing had happened. There is a big risk for that now as well. Which way do you think the post-coronavirus economic recovery will go? It could be that governments do exactly what they know best, like build roads and finance the big carbon-emitting industries. But there is an opportunity…

SOURCE: CARBON BRIEF EXTREME weather is nothing new – storms and floods have been costing human lives since time immemorial. But in recent years, something has been stirring. In 2020 alone there were record-breaking bushfires in Australia and California. Extreme flooding hit many parts of the world, from China and Bangladesh to West Africa. The US hurricane season, meanwhile, saw 30 named tropical cyclones, the highest number recorded and more than double the long-term average of 12 named storms. These included 13 hurricanes, against a long-term average of six. In the US Midwest region a derecho storm – a large system of fast-moving thunderstorms that can whip up very strong winds – caused billions of dollars of crop damage. Adam Smith at the US National Oceanic and Atmospheric Administration (NOAA)…

CHALLENGE 1: ELECTRICITY GENERATION IN THE past few years, the transition to renewable energy has begun in earnest, driven by rapid progress in ramping up wind and solar electricity generation. Something like a quarter of the world’s electricity needs, making up more than 10 per cent of our total energy consumption, is already covered by modern renewable sources, meaning anything but the traditional burning of biomass such as wood and dung. Most pathways to limit warming to 1.5°C, the aspiration set out in the 2015 Paris climate agreement, require at least 50 per cent (and preferably much more) of the world’s energy needs to come from renewables by 2050. That means the almost complete decarbonisation of electricity generation – 100 per cent renewable electricity generation. ↓ See page 64 for…

Hydrogen is the lightest element in the universe and the most abundant. Although it rarely exists on its own on Earth, it can be produced using clean electricity to split essentially inexhaustible water, producing only oxygen as a by-product. Once made, hydrogen acts as a chemical energy carrier, rather like oil or gas, that can be piped or transported to where it is needed. It stores three times as much energy per unit of mass as conventional petrol. When it “burns” in air – releasing that stored energy – it simply combines with oxygen to produce water again. In that sense, it is the ultimate green fuel. Small wonder that across the world, there’s renewed interest in the “ hydrogen economy”, wth hydrogen used as a fuel to decarbonise “hard-to-abate”…

Writing net-zero targets into law, as countries such as the UK and Sweden have done, has a significant, if obvious, consequence: governments can be challenged in court if they enact policies that might fall foul of them. Since enacting its net zero commitment in 2019, the UK government has been the subject of litigation about airport expansion and road building policies. Even without such legally binding targets, climate change is increasingly ending up in the courts based on more general legal principles. In a high profile case in the US, in 2015 a group of “climate kids” sued the US government over its climate change policies, on the basis they violated their constitutional rights to life, liberty and property by not halting global warming. The case was finally dismissed by…

THINK ABOUT THE CHILDREN THE single biggest impact anyone can have on their long-term carbon footprint is to have one fewer child (see graphic, page 88). But this impact is calculated over generations – so won’t contribute much to carbon emissions reductions over the next decade where fast action is required to reduce global warming. ← Chapter 5 has more on population DRIVE OFF Car journeys, especially short ones in cities, account for a disproportionate share of emissions. A third of the carbon dioxide emissions from an average household in the UK, for example, come from road transport. If you can’t live car-free, switching to an electric car can largely eliminate the emissions associated with running one. If you cannot go electric, get a smaller, more fuel-efficient car. Avoid diesel…