The worst climate change denial myths, debunked by experts

Tuesday, 27 November 2018

There's a lot of misinformation about climate change out there. Here are a few myths - and why they're wrong.

Scientific evidence for climate change is 'unequivocal', according to the Intergovernmental Panel on Climate Change (IPCC).

Who are they? The IPCC's latest report, published in October 2018, had 91 authors and 133 contributing authors, over 6000 cited scientific references, and about 42,000 expert and government review comments.

Beyond the IPCC, 97 percent of climate scientists agree climate-warming trends over the past century are very likely due to human activities, according to NASA. Most of the leading scientific organisations worldwide have issued public statements endorsing this position.

But despite the weight of evidence, climate science denial still exists.

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Stuff asked New Zealanders whose work involved climate change what their most hated climate change myths were and to debunk them.

Man-made CO2 has caused an increase of more than 40 per cent in the atmospheric CO2 composition over the industrial era.

Dr Brett Mullan - Niwa principal climate scientist

MYTH: 'Man-made CO₂ emissions are a tiny percentage of total emissions.'

BUSTED: 'Climate change contrarians claim – quite correctly – that human emissions of carbon dioxide are only a small (less than 1 per cent) perturbation to (annual) natural emissions. What they ignore is that these anthropogenic emissions are cumulative year on year and upset the natural balance of the carbon cycle.

This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, shows atmospheric CO2 has increased since the Industrial Revolution. (Credit: Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.)

'Man-made CO₂ has caused an increase of more than 40 per cent in the atmospheric CO₂ composition over the industrial era, and this has long-lasting effects. The natural system has responded by absorbing about 40 per cent of the additional carbon dioxide, but this is not sufficient to prevent the atmospheric concentration continuing to increase ever more rapidly.'

MYTH: 'CO₂ lags temperature.'

BUSTED: 'The simplest response is: 'It's the sun, stupid'. It takes about 5000 years for the Earth to warm out of an Ice Age, and for about the first 1000 years the cause is entirely down to the Sun – specifically to changes in the Earth's orbit which cause more solar radiation to reach high latitudes and melt summer snow.

'After 1000 years, the oceans have warmed sufficiently that they start releasing some of their stored CO₂, and for the next 4000 years carbon dioxide helps boost the warming. Over the full 5000-year period, the solar and greenhouse gas influences are roughly equal.

'If contrarians still argue that CO₂ cannot be both a cause and an effect of warming, ask them to consider increases in wages versus prices. They clearly influence each other. Changes in wages (the analogue to CO₂) cause rapid increases in prices, whereas prices (the analogue to temperature) cause delayed increases in wages.'

MYTH: '(Climate change) Models are unreliable.'

BUSTED: 'The claim is often made that climate models are tuned to fit the present climate. While some tuning is inevitable in modelling such a complex system, the global climate models start from first principles and solve mathematical equations for: the gas laws, the conservation laws (of mass, energy, angular momentum and water substance), transfer of radiation, formation of clouds and precipitation, atmospheric chemistry, and much more.

Planting trees alone is not the answer to dealing with climate change - instead, we need to reduce emissions.

'They are hugely complex, and the very best tool scientists have for simulating climate variations and forecasting future changes.

'The climate models are not perfect, particularly regarding clouds, but are being improved all the time.'

Dr Cate Macinnis-Ng - University of Auckland School of Biological Sciences senior lecturer and Rutherford discovery fellow

MYTH: 'That higher concentrations of CO₂ in the atmosphere are good for plants.'

BUSTED: 'While higher concentrations of CO₂ in the atmosphere can have a fertilisation effect on plants (because CO₂ is essential for photosynthesis), any gains are limited by the availability of nutrients (like nitrogen and phosphorus).

'In any case, increased occurrence of extreme events such as droughts, heat waves and fire weather are likely to cause more frequent mortality events for trees and other plants.'

MYTH: 'That cold snaps are an indication that climate change isn't happening.'

Temperature data showing rapid warming in the past few decades. According to NASA data, 2016 was the warmest year since 1880, continuing a long-term trend of rising global temperatures. The 10 warmest years in the 138-year record all have occurred since 2000, with the four warmest years being the four most recent years.

BUSTED: 'Climate change leads to higher average temperatures but it also leads to more extreme events that are becoming more severe and less predictable.'

MYTH: 'Planting trees is the answer to reversing climate change.'

BUSTED: 'While I'm a huge fan of trees, planting trees alone is not the answer. Trees remove CO₂ from the atmosphere but we need to make sure conditions are suitable for tree survival and this is likely to become more difficult in a changing climate. Reducing emissions is the best way to reduce CO₂ in the atmosphere.'

Some coastal New Zealand communities are already affected by issues related to climate change. Granity, on the West Coast, is subject to regular inundation.

**Charlie Mitchell - Stuff national correspondent specialising in environmental coverage**

MYTH: 'The Earth would have been warming anyway, humans are just adding to it.'

BUSTED: 'The myth that natural variability in the Earth's climate is partly responsible for recent global warming is a common one. The truth, however, is that it's likely nearly all of the warming since 1950 can be attributed to human-related greenhouse gas emissions.

Cold snaps aren't proof that climate change isn't happening. Weather events are expected to become more variable and more extreme.

'The most recent US National Climate Assessment, released in 2017, estimated between 93 per cent and 123 per cent of warming between 1951 and 2010 was caused by humans, meaning it's possible that without human-related greenhouse gas emissions, the Earth would be on a slight cooling trend, due to natural factors such as volcanic eruptions and solar activity. A similar conclusion was found in the IPCC's last major report in 2013.

MYTH: 'Sea-levels have only risen around 20cm over the last century, so there's nothing to worry about.'

BUSTED: 'It's true that the sea has risen, on average, around 20cm over the last century in much of the world, including New Zealand. But the rate of sea-level rise is not static, and the past rate tells us little about the future rate: The sea is rising much more quickly, and will continue to do so in the coming century, and potentially beyond.

'The most recent measurements around New Zealand show the sea is rising around 3-4mm a year, twice as fast as the average rate for much of the 20th century. Experts expect that rate to continue to accelerate.

'Sea-levels are among the slowest responders to climate change, but also among the most reliable indicators of a warming climate. The last time the Earth was 2C warmer than the pre-industrial era (the target under the Paris Agreement), the seas were 5m higher than today, and likely rose to that level over thousands of years.'

Dr Jim Salinger, climate scientist

If we want to keep global warming to well below 2C, that means 80 per cent of the known fossil fuel deposits cannot be burnt.

MYTH: 'Global cooling is occurring, not warming (the ice age is coming).'

BUSTED: 'There have been many periods in Earth's history that were warmer than today - for example, the last interglacial (125,000 years ago) or the Pliocene (three million years ago). Those variations were caused by solar forcing (heating and cooling), the Earth's orbital wobbles or continental configurations; but none of those factors is significant today compared with greenhouse warming.

'The additional forcing (heating) caused by extra greenhouse gases started since 1850, resulting in heating the surface and lower atmosphere.'

MYTH: 'The earth has been warmer in the recent past - the medieval warm period etc.'

BUSTED: 'Evidence for a Medieval Warm Period outside Europe is patchy at best and is often not contemporary with the warmth in Europe. As the US National Oceanographic and Atmospheric Administration puts it: 'The idea of a global or hemispheric Medieval Warm Period that was warmer than today has turned out to be incorrect'.

'Additionally, although the Arctic was warmer in the 1930s than in the following few decades, it is now warmer still. One recent analysis showed it is w armer now than at any time in the last 2000 years.'

Elisabeth Ellis - University of Otago associate professor and Deep South Challenge lead researcher

MYTH: 'That participating in the existing fossil fuel energy regime is the same as endorsing the existing fossil fuel energy regime.'

BUSTED: 'From an individual perspective, we are born into constellations of systems that constrain all our actions as if they were natural. One of these systems, for example, is 'automobility'. Automobility is a social convention: it is almost impossible to opt out on your own, and if we want to change it, we have to do that together. But we don't get to choose our social conventions all at once: that's what makes them so hard to change.

'Another way to talk about this myth is to say that attributing responsibility for the present energy regime to individuals is a mistake. This widespread and dangerous mistake disempowers individuals by assigning them responsibility for something that they cannot change.'

MYTH: 'That some single technological innovation will save us. [That some form of technology] will make political action to respond to climate change unnecessary.'

BUSTED: 'Hoping for a technological silver bullet is a mistake for lots of reasons: it encourages us to delay taking the steps we need to take now to plan for a changing climate; it positions us as patients rather than agents with regard to our common destiny; it mischaracterises a problem of collective action as a technical problem. Of course, improved technologies will play an essential role in our transition to sustainability. But not one of them – in fact, not all of them together – will relieve us of the need to coordinate our actions better. Coordination can take many forms, from price signals to regulation to social norms like what counts as cool. Without it, even the most rapid and unexpectedly successful technological innovations will not be able to sustain human flourishing.'

Anita Wreford - Lincoln University associate professor and Deep South Challenge lead researcher

MYTH: 'Humans have always adapted to change and climate change is no different.'

BUSTED: 'I think that the pace and magnitude of the changes we face will be different from what we have seen before. Also, the ways in which we have made decisions in the past (particularly focusing on the short term) may turn out to be maladaptive and leave us more exposed to future climate and other risks.

'Something else I hear often is that 'while climate change won't be too difficult to adapt to… it's the extreme events that will be hard'. It's important to distinguish between gradual and relatively predictable 'global warming' and the uncertainty of 'climate change'. Even some relatively informed people seem to forget that climate variability and extremes are part of the package.'

Bronwyn Hayward - University of Canterbury associate professor and co-lead author of the IPCC's recent 1.5C special report

MYTH: 'The problem is caused by a few large nations, and small countries like New Zealand are minor contributors.'

BUSTED: 'Many of us as individuals have very high greenhouse gas footprints. Last year, New Zealand's gross emissions per person were the seventh highest among the 41 industrialised countries. That means as individuals, many of us are amongst the top 10 percent of high emitters globally. This matters, because as Kevin Anderson, Professor of Energy and Climate Change at the University of Manchester argues, if people like us were to reduce our carbon footprints to the level of the average European, we would be able to achieve a one-third cut in global emissions in one year.

'New Zealand is the second largest exporter of dairy products in the world. In 2016, New Zealand's agriculture sector was the largest contributor to our gross emissions, at 49.2 per cent. We are a world leader in agriculture and what we do matters globally to methane, to carbon and to the world's vision of what is possible.'

MORE CLIMATE CHANGE MYTHS BUSTED

The website Skeptical Science also has a list of common climate change myths and uses scientific evidence to debunk each one. There are a lot - almost 200.