As the time approaches when climate change will start seriously disrupting life, here's what you need to know.
It’s all part of the “new normal”, says global reinsurer Munich Re, which describes last year’s weather catastrophes as a “foretaste of things to come” in a warming climate. Insurers understand the cost of climate change better than most – last year’s extreme weather events have left the industry with a record bill of US$135 billion ($186 billion).
For New Zealand, too, last year was the most expensive ever for weather-related damage, with the insurance industry paying out $242 million. Wildfires tore across Christchurch’s Port Hills, the remnants of Cyclone Debbie caused devastating floods, and in July, Oamaru experienced its wettest day on record – three times its previous one-day record for that month.
So far this year, we have sweated through hot days – Dunedin Airport hit a record of 35°C in the middle of the month, and Invercargill experienced its second-hottest day on record, at 32.3°C – and sweltering nights. Across the Tasman, Sydneysiders have suffered through extreme heat that saw the suburb of Penrith reach a record 47.3°C.
Such conditions offer a glimpse of what the future will be like as a result of human-induced climate change. As Victoria University professor of physical geography James Renwick points out, the world has already warmed by about 1°C since the 19th century. Two degrees of warming will bring treble the number of very hot days for New Zealand, treble the number of droughts, wide-ranging fire danger and double or treble the number of major floods.
“The way we experience climate change and sea-level rise is through extreme events,” he says. “And the climate is clearly changing, as recent heat waves, wildfires, flooding rains, and coastal inundation attest.”
Like the 196 other countries signed up to the Paris climate accord, New Zealand needs to act rapidly over coming decades to keep temperature increase as close as possible to 1.5°C, to avoid the worst impacts of climate change. Here's why.
1. In a world that’s 2°C warmer, we will experience dangerous climate change
The words “two degrees” trip off the tongue. They’ve become part of the global climate shorthand, abbreviating the existential threat of global warming to a simple, easy-to-remember mega-target. The international consensus that a rise in average global temperature should be limited to no more than 2°C compared with pre-industrial times is often described as a “guardrail”: provided we stay inside the railing, we will be fine; if we venture beyond it we will be unsafe.
But it is foolhardy to think that a 2°C world will be benign. Climate scientist Kevin Anderson, of the Tyndall Centre for Climate Change Research in the UK, has said that 2°C represents a threshold not between acceptable and dangerous, but between dangerous and extremely dangerous climate change.
Veteran climate scientist James Hansen, who first testified before the US Senate committee on energy and natural resources in 1988, says 2°C is not the safety margin it is often understood to be. Instead, it would represent “disastrous” climate change, with some regions suffering “unbearable summer heat, ecological collapse, species extinction, widespread famine, coastal cities lost to rising seas … and national and international conflict”.
Victoria’s Renwick says the incidence of extreme heat and major floods will double or triple, and eastern regions of New Zealand will be at acute risk of wildfire for four to six months of the year. High fire danger tends to be a feature of mid-Canterbury, northern Hawke’s Bay and Gisborne, but in a 2°C warmer world the fire zone will extend from East Cape to South Otago.
The big glaciers that draw international tourists will probably disappear from view. “Even if we get to 2°C and stop there, the glaciers might not disappear completely, but they would recede up their valleys so far that, to all intents and purposes for the tourist trade, it will be as if they have disappeared completely,” says Renwick.
How will life be for ski bunnies? We can probably forget about skiing and boarding the fields of the Central Plateau by the end of this century. Renwick predicts snowmaking will keep working for another 20 to 30 years, enabling enough artificial snow on the main runs to keep things going, but by the second half of this century, North Island ski fields will be “marginal at best”. In the southern South Island, skiing may remain viable, although with a shorter season. With each 1°C of warming, he notes, the snow line recedes about 150m.
Living in a 2°C warmer world has political ramifications, too. As rising seas make parts of low-lying Pacific islands uninhabitable, more people will want to move to New Zealand. At the same time, the world’s wealthy may see this country as a bolthole from climate-induced instability.
“If we get a substantial amount of sea-level rise and temperature extremes become much more prevalent in the tropics and rice crops start failing and so on, and you start to have millions of people wanting to move,” says Renwick, “how will we deal with that?”
2. Climate change isn’t just a problem for future generations: it’s happening now
It’s been a long hot summer and we are only halfway through it. Sam Dean, Niwa’s chief climate, atmosphere and hazards scientist, is confident human-induced climate change has played a big part in this year’s baking temperatures. “There is no doubt that this kind of heat has an anthropogenic [man-made] contribution from climate change.”
That’s not to say that exceptionally high early-summer temperatures could not have occurred without the influence of climate change, but the chances of that happening would have been tiny. This summer is also influenced by the La Niña effect, but the climate change impact is significant, he says.
Dean works in the fast-developing field of climate attribution science, studying the extent to which global warming is influencing extreme weather events. High temperatures are the easiest type of weather to trace back to climate change, he says, because “as you emit carbon dioxide, the atmosphere warms up. It’s a first-order response.”
For the past six years, the American Meteorological Association has published an annual collection of studies on extreme weather events. Dozens of studies have found that climate change has increased the odds of such extremes, but late last year – for the first time – three studies concluded that certain weather events would not have happened without human-induced climate change. They were the record global temperatures of 2016; an extreme heat wave that hit Asia that year; and an area of persistently warm ocean water off Alaska, known as “the Blob”.
The searing temperatures, as high as 45°C, in New South Wales in February 2017 have also been attributed to climate change. The World Weather Attribution (WWA) project – a collaboration between Oxford University, the Royal Netherlands Meteorological Institute, University of Melbourne, Red Cross/Red Crescent, and Climate Central – crunches observational data, peer-reviewed research and on-the-ground reports to identify the fingerprint of climate change on extreme events. The researchers concluded that the record average summer temperatures of 2016/17 were 50 times more likely because of climate change. WWA has not yet published any analysis of the extreme heat experienced recently in Australia, with Sydney hitting 47.3°C in January.
What about the hurricanes that smashed into the US Gulf Coast and Caribbean in 2017? Research published last month showed climate change played a significant role in Hurricane Harvey, which battered the Caribbean and the south-eastern US in August. One study found climate change had increased the intensity of the storm by at least 19%, and another found that the same cause had made the record rainfall over Houston three times more likely and 15% more intense. The researchers said that because warmer air can carry more moisture, it can lead to more extreme rainfall, and warmer ocean-surface temperatures are known to intensify powerful hurricanes.
Dean says climate change is not expected to increase the number of cyclones (as hurricanes are called in our part of the world), but those that do occur will be more intense. These megastorms are formed when the ocean’s surface temperatures are high for a prolonged period. This will become more likely, but he says the evidence suggests climate change will cause wind shear in the tropical atmosphere to increase, cancelling out the effects of warming waters.
“But when they do happen, it’s in an environment when the sea-surface temperature is higher, so they will be bigger and more powerful. New Zealand doesn’t usually get tropical cyclones – mostly we are impacted by former tropical cyclones that have lost their warm core and transitioned to low-pressure systems – and we would expect the same number of those. They will be carrying more moisture and stronger winds and will therefore be more destructive, but we don’t per se expect any increase in frequency.”
3. It’s still possible to limit warming to 1.5°C – just
When the Paris climate accord was signed in April 2016, there was jubilation, not only because a global agreement had finally been reached but also because the level of ambition had increased. Until then, the focus had been on limiting global warming to no more than 2°C, beyond which climate change would unleash intolerable instability. But thanks to the efforts of small vulnerable island states, the world’s leaders agreed in Paris to “pursue efforts” to limit temperature increase to 1.5°C.
But at the time, no one knew if this was achievable, given that the planet had already warmed by about 1°C. Some scientists were critical of the world’s climate diplomats for signing up to a goal they considered unrealistic. But recent research has concluded that the 1.5°C goal is not yet out of reach. “Our calculations suggest that staying below 1.5°C looks scientifically feasible, if extremely challenging,” wrote two of the co-authors of the study, David Frame of Victoria University and Damon Matthews from Concordia University in Montreal, in The Conversation.
It all comes down to how much room we have left in the global carbon “budget”. This is the total amount of greenhouse gas emissions consistent with a particular temperature target. The carbon budget is a critically important piece of information in the battle to limit warming. Just as a household budget requires you to restrict your spending to avoid going into overdraft, the carbon budget tells us how much we can afford to dump into the atmosphere without pushing the climate above a given threshold.
The Oxford University-led research group concluded that the carbon budget consistent with the 1.5°C goal was larger than previously thought. However, meeting the target would require emissions to fall by 4-6% a year for several decades.
That might not sound like much, but Frame and Matthews point out that such declines have historically been seen during periods like the Great Depression, the aftermath of World War II and the collapse of the Soviet Union. At the same time, “there is no historical analogy to show how rapidly human societies can rise to … the matrix of problems (and opportunities) posed by climate change. We do not really know how fast we can decarbonise an economy while improving human lives, because so far we haven’t tried very hard to find out.”
4. It’s probably a good time to rethink that waterfront property
Whether it’s a bach or a permanent home, a beachfront property is part of the Kiwi dream. But that dream will become an expensive nightmare. Sea levels have already risen by 20cm since the start of the 20th century and a further rise of about 30cm is expected by 2065. Even if aggressive efforts are made to reduce greenhouse-gas emissions to zero in coming decades, the sea level will continue rising for centuries.
Higher seas, combined with king tides and increasingly frequent severe storms, will mean more coastal flooding and erosion, and elevated groundwater. Even a modest (30-40cm) sea-level rise by mid-century will turn one-in-100-year storm-tide floods into annual events, according to advice by the Ministry for the Environment.
Almost 300,000 New Zealanders live less than 3m above mean high-water spring tide. Homes and buildings worth $52 billion are located within that zone, along with roads, railway lines and airports.
For now, bankers are still lending money to people wanting to buy coastal property and insurers are still – with a handful of exceptions – offering all-perils insurance. But that seems certain to change.
In the case of coastal properties vulnerable to coastal erosion and tide surges, bankers expect a “gradual reduction in the extent to which they could lend against those properties and/or they will also require a higher level of equity from the borrower to issue a loan or they will likely apply a penalty interest rate”, according to a 2016 report, “Climate Change Impacts and Implications for New Zealand to 2100”.
Insurance Council chief executive Tim Grafton says properties experiencing more frequent flooding will become “less and less insurable”. And if a property is not insurable, banks won’t lend on it, which means it will become less and less saleable.
“If you get [situations] where a bank says, ‘Well, you want to buy this $2 million property beside the sea – we’ve looked at it and all the predictions say it will become pretty much uninsurable. There’s an 80% chance it won’t happen in five years, but maybe a 50% chance it could happen in five to 10 years, so we’ll give you a five-year mortgage’. At that point the affordability of the property is restricted to people with a whole lot of money who can afford to buy with only a five-year mortgage. And as the market gets smaller, the value of the property is going to drop.”
5. The future of the ice sheets will determine how bad things get
If not for the oceans, the planet would already be uninhabitable. About 93% of the atmospheric heating caused by humanity since the start of the Industrial Revolution has been absorbed by the oceans. The seas have cushioned the impact of climate change in the short term, but now those warmer waters are eating into the ice sheets.
By mid-century, the average global sea level will have risen 50cm in 150 years; the extent to which seas rise more than this – and how rapidly – depends very much on what happens to the frozen masses of Antarctica and Greenland. The huge West Antarctic ice sheet sits on bedrock 2km or more below the sea. As the temperature of the sea increases, the warmer water gets under the ice, melting and destabilising it from below.
The Pine Island and Thwaites glaciers are key areas of concern, and are thought to be Antarctica’s biggest contributors so far to rising sea levels, says associate professor Nick Golledge, of Victoria University’s Antarctic Research Centre. Some researchers have concluded that parts of the West Antarctic ice sheet are already in irreversible retreat, although Golledge says this finding remains controversial.
More recently, concern has grown that parts of the vast East Antarctic ice sheet – long assumed to be more stable than the West – are also vulnerable. Research published last year, co-authored by Victoria University Antarctic researcher Tim Naish, concluded that if CO2 emissions continue on their current path and reach 600 parts per million by the end of this century (currently they exceed 400ppm), melting from the East Antarctic ice sheet would eventually lead to massive sea-level rise.
The melting of the Greenland ice sheet is caused primarily by warmer air rather than warmer seas, because it sits largely on rock above sea level and is subjected to air temperatures that are rising at rates far above the global average. The huge Jakobshavn Glacier alone contains the equivalent of 60cm of sea-level rise, and is retreating at about 600m a year, says Emily Shuckburgh, co-leader of oceanography at the British Antarctic Survey in Cambridge, UK.
Melting ice sheets also create a dangerous feedback loop, Golledge says. Melted ice flows as freshwater into the ocean, which sits as a layer near the surface. Because freshwater freezes more easily, it may cause more sea ice to form and keep the local atmosphere cooler. But the freshwater layer causes the ocean to become more stratified. “That means the warmer water from below, which would otherwise be brought up and mixed by the wind, can’t go anywhere,” he says. “It remains trapped at a depth where it melts the base of the ice sheet.”
Golledge’s research shows that fresh water from melting Antarctic ice could disrupt global ocean circulation, leading to climatic changes in the Northern Hemisphere.
Similarly, the freshening of Arctic waters as a result of melting sea ice and diminishing Greenland glaciers is affecting the ocean circulation system of the Atlantic, with huge implications for the North Atlantic climate, says Shuckburgh.
6. The good news is that there is plenty of good news
The price of renewable energy worldwide is plummeting and the level of investment in renewable generation is soaring. There’s still a long way to go before climate-warming fossil fuels are sidelined, but a profound shift in favour of green energy is under way.
Last May, an article in the Financial Times described a “wave of disruption … After years of hype and false starts, the shift to clean power has begun to accelerate at a pace that has taken the most experienced experts by surprise.”
Oil, gas and coal still account for 86% of the world’s energy needs, and the International Energy Agency predicts demand for fossil fuels will continue rising until at least 2040. But solar photovoltaic panels were the world’s leading source of additional electricity generation in 2016, according to the Renewable Energy Policy Network (REN21), with the equivalent of 31,000 solar panels installed every hour.
Since 2010, the average cost of onshore wind generation has fallen 23% and the cost of power from solar photovoltaic panels is down by 73%, according to a report released this month by the International Renewable Energy Agency (IRENA). The organisation expects the cost of solar generation to halve again by 2020, and says all renewable energy should be price-competitive with fossil fuels by that date. It reports that US$1 trillion has been invested in renewables since 2013, and the sector now employs 10 million people.
Much of the clean-energy momentum is coming from China and India. According to REN21, for the billion citizens of developing nations without access to reliable electricity or who are far from a national grid, decentralised renewables such as solar panels are offering “important and often cost-effective options” for electricity.
The cost of lithium-ion batteries – crucial to the affordability of electric vehicles – is also falling fast, down 73% since 2010 and likely to fall another 75% by 2030, according to Bloomberg New Energy Finance.
And 2017 was a year of groundbreaking announcements indicating the shift away from fossil-fuel-guzzling vehicles is accelerating. More than 20 countries, states and cities – including France, the UK, China, India, Scotland, California, Athens, Madrid and New Mexico – announced future bans on petrol- and diesel-powered vehicles. Chinese-owned car maker Volvo said it would stop designing fossil-fuel cars from 2019, and Tesla has showcased an electric truck capable of travelling 400km on a single charge.
The year closed with the World Bank saying it would no longer finance oil and gas exploration, other than in “exceptional circumstances” for the poorest countries if there was a “clear benefit in terms of energy access” and the project fits within the countries’ commitments under the Paris Agreement. At the same time, 225 institutional fund managers (including the New Zealand Superannuation Fund) responsible for US$26.3 trillion in investors’ savings announced an effort to pressure the world’s biggest carbon emitters to start shifting to a more climate-friendly mode of business.
And, in a sign of mounting pressure on oil, gas and coal companies to bear the cost of climate change, the City of New York filed a lawsuit against the five biggest fossil-fuel companies for the costs of protecting the city’s residents from the effects of increasingly severe heat waves, extreme rain and sea-level rise. The lawsuit alleges the companies “produced, marketed and sold” fossil fuels for years despite knowing they produced emissions that caused “grave harm” to the climate system. The suit adds to a growing body of climate-related litigation around the world against both fossil-fuel companies and governments that are perceived to be too slow to act on climate change.
7. We’ll have to suck it up
Even if we stopped using fossil fuels tomorrow, it wouldn’t be enough to stabilise the temperature at less than 2°C above pre-industrial levels. To do that, we will also have to suck CO2 out of the atmosphere.
Carbon dioxide concentrations are at their highest level in 800,000 years, averaging 403.3 parts per million in 2016, according to the World Meteorological Organisation. “The last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago, the temperature was 2-3°C warmer and sea level was 10-20m higher than now,” it reported last October.
The CO2 molecules we release today – by driving to work or the supermarket in our fossil-fuelled car, for instance – will stay in the atmosphere “for hundreds if not thousands of years”, says Massey University energy expert Ralph Sims. “It’s cumulative; it does not diminish with time. So if we can pull some of those molecules out of the atmosphere and lock them up somewhere, then that 403ppm decreases, so we have less concentration in the atmosphere and less global warming forcing effect.”
How can we do that? One important way is by growing trees where there are currently none – either by planting the likes of fast-growing radiata pine or allowing land to revert to native forest. “As long as the forest stays there, the carbon dioxide used in photosynthesis is taken out of the atmosphere and locked up as biomass in the tree,” says Sims.
Forestry will be a key tool in New Zealand’s efforts to manage its greenhouse gas emissions. Experts at the University of Canterbury’s School of Forestry have mapped out approximately 1.3 million hectares of erosion-prone land that could be turned over to carbon-sequestering trees.
Sims says another method is to increase soil carbon by adding more straw and green cover crops, and also by adding biochar. This is woody biomass (for instance, branches from a forest that has been logged) that’s turned into charcoal by heating it at a high temperature in the near-absence of oxygen. “That charcoal is mainly carbon, and you can then pulverise it and put into the soil where it is locked up.” The fertility of some soil types is boosted by this process.
But the method of CO2 removal that’s central to the United Nations’ Intergovernmental Panel on Climate Change climate forecasts is bioenergy with carbon capture and storage, known as BECCS. This is a process by which crops or trees are burnt to produce energy, with the resulting emissions captured and pumped deep underground, using the same technology that has long been used in the oil industry to extract the last drops from oil wells.
But there are lots of unknowns, including the implications for land use and water consumption from growing large scale BECCS crops. And, in the absence of a realistic price on carbon that would create the necessary incentive, there have so far been no large-scale demonstration plants to prove its viability, says Sims.
8. Health warning
If you are inclined to think that climate change is largely a problem for other people in faraway places, research by Canterbury Museum arachnologist Cor Vink may jolt you out of your complacency. Vink has closely studied the venomous redback spider and its incursion into New Zealand’s warm, dry places.
The Australian arachnid was first seen in New Zealand in the early 1980s, near Glendhu Bay, a popular holiday spot a few kilometres from Wanaka. Since then, it has taken up residence in Alexandra and Bannockburn (near Cromwell), and there have been recent sightings in Queenstown. Vink says as New Zealand’s eastern regions get warmer and drier, the potential habitat for the redbacks will expand.
He says they are shy creatures, but if they bite, they cause serious illness. “The best description I’ve heard is, ‘You probably won’t die, you’ll just feel as if you are going to’.”
A warmer climate will also bring other health risks, which are spelt out in a 2017 report by the Royal Society. Rising sea temperatures and changing currents could lead to the permanent establishment in New Zealand waters of toxic marine algae, which can contaminate shellfish and cause ciguatera fish poisoning if consumed. Similarly, the risk of toxic blue-green algal blooms in freshwater is likely to increase as a result of warmer water, lower flows and increased nutrient run-off from land during heavy downpours. Contact or ingestion can cause liver damage, skin disorders and gastrointestinal, respiratory and neurological symptoms.
More extreme rainfall and higher temperatures are also likely to interact with agricultural run-off to increase the incidence of water-borne diseases such as campylobacter, which poisoned the drinking water of Havelock North in 2016. The report says the same factors are also likely to increase the risk from parasites, such as giardia or cryptosporidium, and bacterial infections such as salmonella, E coli and leptospira (which is introduced into water from the urine of infected animals).
Communities affected or displaced by sea-level rise will experience a rise in mental illness. And an increase in the number of very hot days will bring greater risk of heat-related deaths especially among the elderly. Asthma sufferers are likely to be worse off, as longer growing seasons mean more pollen.
And we can expect heightened risk of mosquito- and tick-borne diseases that are currently absent from New Zealand, such as the West Nile virus and dengue fever. The risk of emerging pathogens such as the Zika virus could also increase with higher temperatures and changing precipitation patterns.
9. Don’t just stand there. Do something
The advice from climate scientists is clear and unambiguous. As Johan Rockström, this year’s Hillary Laureate and director of the Stockholm Resilience Centre, has put it, “We need to bend the global curve of emissions no later than 2020, and reach a fossil-fuel-free world economy by 2050. Yes, this is a grand transformation. Is it doable? Yes. Is it a sacrifice? No. The evidence grows day by day that a decarbonised world is a more attractive world.”
The massive cuts to emissions that are needed will be driven primarily by the policies set by governments, the establishment of a price on carbon that reflects the true cost of greenhouse-gas pollution and the emergence of low-carbon technologies.
The Government intends to introduce legislation that will commit New Zealand to carbon-neutrality by 2050, and set up an independent climate commission. Climate Change Minister James Shaw is promising extensive consultation this year, before drafting a Zero Carbon Act. National Party climate spokesman Todd Muller has welcomed consultation, to avoid “shock and pain” to established sectors, and is “particularly interested” in testing how a “successful model” like the UK-style climate committee could work here.
Per capita, New Zealanders are the fifth-highest greenhouse-gas emitters in the OECD, according to the Ministry for the Environment. These steps can help us produce less CO2.
- Drive less often.
- Reduce household food waste.
- Eat less red meat and more plants.
- Reduce long-haul plane travel, and when you fly, buy carbon credits to offset your emissions.
- When you need to replace your car, choose a fuel-efficient one, or go electric.
- Recycle or, preferably, reuse.
This article was first published in the August 19, 2017 issue of the New Zealand Listener.