Climate explained: are we doomed if we don’t manage to curb emissions by 2030?

Thongden Studio/Shutterstock

Robert McLachlan, Massey University

CC BY-ND

Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.

If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz

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Is humanity doomed? If in 2030 we have not reduced emissions in a way that means we stay under say 2℃ (I’ve frankly given up on 1.5℃), are we doomed then?

Humanity is not doomed, not now or even in a worst-case scenario in 2030. But avoiding doom — either the end or widespread collapse of civilisation — is setting a pretty low bar. We can aim much higher than that without shying away from reality.

It’s right to focus on global warming of 1.5℃ and 2℃ in the first instance. The many manifestations of climate change — including heat waves, droughts, water stress, more intense storms, wildfires, mass extinction and warming oceans — all get progressively worse as the temperature rises.

Climate scientist Michael Mann uses the metaphor of walking into an increasingly dense minefield.

Good reasons not to give up just yet

The Intergovernmental Panel on Climate Change described the effects of a 1.5℃ increase in average temperatures in a special report last year. They are also nicely summarised in an article about why global temperatures matter, produced by NASA.

The global average temperature is currently about 1.2℃ higher than what it was at the time of the Industrial Revolution, some 250 years ago. We are already witnessing localised impacts, including the widespread coral bleaching on Australia’s Great Barrier Reef.

This graph shows different emission pathways and when the world is expected to reach global average temperatures of 1.5℃ or 2℃ above pre-industrial levels.
Global Carbon Project, Author provided

Limiting warming to 1.5℃ requires cutting global emissions by 7.6% each year this decade. This does sound difficult, but there are reasons for optimism.

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First, it’s possible technically and economically. For example, the use of wind and solar power has grown exponentially in the past decade, and their prices have plummeted to the point where they are now among the cheapest sources of electricity. Some areas, including energy storage and industrial processes such as steel and cement manufacture, still need further research and a drop in price (or higher carbon prices).

Second, it’s possible politically. Partly in response to the Paris Agreement, a growing number of countries have adopted stronger targets. Twenty countries and regions (including New Zealand and the European Union) are now targeting net zero emissions by 2050 or earlier.

A recent example of striking progress comes from Ireland – a country with a similar emissions profile to New Zealand. The incoming coalition’s “programme for government” includes emission cuts of 7% per year and a reduction by half by 2030.

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Third, it’s possible socially. Since 2019, we have seen the massive growth of the School Strike 4 Climate movement and an increase in fossil fuel divestment. Several media organisations, including The Conversation, have made a commitment to evidence-based coverage of climate change and calls for a Green New Deal are coming from a range of political parties, especially in the US and Europe.

There is also a growing understanding that to ensure a safe future we need to consume less overall. If these trends continue, then I believe we can still stay below 1.5℃.

The pessimist perspective

Now suppose we don’t manage that. It’s 2030 and emissions have only fallen a little bit. We’re staring at 2℃ in the second half of the century.

At 2℃ of warming, we could expect to lose more than 90% of our coral reefs. Insects and plants would be at higher risk of extinction, and the number of dangerously hot days would increase rapidly.

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Read more:
Not convinced on the need for urgent climate action? Here’s what happens to our planet between 1.5°C and 2°C of global warming

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The challenges would be exacerbated and we would have new issues to consider. First, under the “shifting baseline” phenomenon — essentially a failure to notice slow change and to value what is already lost — people might discount the damage already done. Continuously worsening conditions might become the new normal.

Second, climate impacts such as mass migration could lead to a rise of nationalism and make international cooperation harder. And third, we could begin to pass unpredictable “tipping points” in the Earth system. For example, warming of more than 2°C could set off widespread melting in Antarctica, which in turn would contribute to sea level rise.

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If warming exceeds 2°C, Antarctica’s melting ice sheets could raise seas 20 metres in coming centuries

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But true doom-mongers tend to assume a worst-case scenario on virtually every area of uncertainty. It is important to remember that such scenarios are not very likely.

While bad, this 2030 scenario doesn’t add up to doom — and it certainly doesn’t change the need to move away from fossil fuels to low-carbon options.

Robert McLachlan, Professor in Applied Mathematics, Massey University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Humans see just 4.7km into the distance. So how can we truly understand what the bushfires destroyed?

Jamie Pittock

Nanda Jarosz, University of Sydney

When the ashes from Australia’s last bushfire season cooled, we were left with a few mind-boggling numbers: 34 human lives lost, more than a billion animals dead, and 18.6 million hectares of land burned.

But those figures don’t necessarily help us understand what was lost. The human mind struggles to grasp very large scales. And in Australia, our colonial past skews the way we view landscapes today.

This disconnect is important. Many scientific concepts, including climate change, happen at scales outside human perception.

Understanding the scale of destruction wrought by bushfires is vital if governments and societies are to adapt in the future. So how can Australians truly come to terms with the damage wrought by last summer’s bushfires?

More than a billion animals died in last summer’s fires.
Daniel Mariuz/AAP

Beyond human perception

On average, humans can only see about 4.7 kilometres into the distance. So perceiving the true extent of the destruction bushfires requires using our imaginations.

This is not only true of bushfires. It also applies to human understanding of climate change, nanoseconds, the size of the Universe and the geological time scale (the millions of years over which continents, oceans and mountains formed).

But science has shown humans have trouble understanding, or imagining, large orders of magnitude. In one US study for example, university students struggled to understand the relative relationships between the age of the Earth, the time required for the origin of the first life forms, and the evolution of dinosaurs and humans.

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Even university students studying STEM subjects (science, technology, engineering and mathematics) have been shown to struggle with identifying and comparing magnitudes at large scales.

So what’s actually going on in our brains here? Research suggests humans use both numerical and “categorical” information – concepts drawn from their prior experience – to estimate the size of an object. For example, a person estimating the width of a truck might set it as a proportion of the presumed width of highway lanes.

The use of this prior experience can improve the accuracy of estimations. But it can also introduce bias and lead to inexact estimations.

Even university students studying STEM subjects struggled to comprehend large orders of magnitude.
Shutterstock

Understanding vast landscapes

During the fires, satellite images and interactive maps sought to help us understand the scale of the crisis. But they can’t give a full picture of the life destroyed. So how might we otherwise understand the richness lost in a burnt landscape?

Unfortunately, our colonial views of the land are not much help here. British colonisation of Australia, and subsequent land laws, were established on the basis of “terra nullius” – meaning the land belonged to no one. This denied Indigenous people’s prior occupation of the land in order to legitimise its “lawful” settlement by Europeans.

Settlers tended to describe the Australian landscape as empty and unpopulated when, in fact, it was biologically [abundant] and peopled by Indigenous Australians.

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These colonial views have had lasting effects. It took more than 200 years before the terra nullius myth was formally dispelled by the 1992 Mabo decision.

Seeking to understand Indigenous perspectives of Country might help non-Indigenous Australians to truly comprehend the loss brought by bushfires. As Indigenous academic Bhiamie Williamson wrote on The Conversation in January:

the experience of Aboriginal peoples in the fire crisis engulfing much of Australia is vastly different to non-Indigenous peoples. How do you support people forever attached to a landscape after an inferno tears through their homelands: decimating native food sources, burning through ancient scarred trees and destroying ancestral and totemic plants and animals?

A human-centric view

Beyond the colonial influence, our generally human-centred view of the world also tends to render invisible the plants and wildlife within it. As Australian researcher Brendan Wintle and others noted in a recent paper, firefighting strategies routinely overlook the need to protect natural assets. They wrote:

It may be unrealistic to expect critical habitats of our most precarious species to compete for firefighting resources with houses and farms. We are far too self-interested. However, could we imagine the last remaining habitat for a brush-tailed rock-wallaby (Petrogale penicillata) might feature as an asset for protection in a fire that is burning through a wilderness area? Surely that needs doing.

In other words, gaining a better understanding the scale of a fire’s destruction means taking a more holistic view of what dwells in the landscape, and might need saving.

Rock wallaby habitat should be protected from fire.
Taronga Zoo

Future fires

Under climate change, bushfires in Australia will become more severe and frequent. So bearing in mind our limited abilities to perceive the potential scale of loss next time, what can we do to prepare?

As Wintle argues, more work is needed to organise conservation efforts before, during, and immediately after a bushfire. That includes establishing “insurance populations” of species and keeping them out of harm’s way, and better monitoring and surveying before a fire, so we know which places need protecting.

Williamson wrote of how most Indigenous Australians “have been consigned to the margins in managing our homelands”, watching on as they were “mismanaged and neglected”, which increased the bushfire risk.

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The current bushfire royal commission has pledged to consider ways Indigenous land and fire management practices could improve our resilience to natural disasters. There is much room for ancient traditions to be incorporated into mainstream fire management.

It will take some time to grasp the repercussions of the last bushfire season. But it’s clear that we must transcend colonial, non-Indigenous, human-centred perceptions of the land if we’re to truly understand what was lost.

Nanda Jarosz, PhD Candidate, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.