This week’s release of the special report from the Intergovernmental Panel on Climate Change (IPCC) has put scientific evidence on the front page of the world’s newspapers.
As Australia’s Chief Scientist, I hope it will be recognised as a tremendous validation of the work that scientists do.
The people of the world, speaking through their governments, requested this report to quantify the impacts of warming by 1.5℃ and what steps might be taken to limit it. They asked for the clearest possible picture of the consequences and feasible solutions.
It is not my intention in this article to offer a detailed commentary on the IPCC’s findings. I commend the many scientists with expertise in climate systems who have helped Australians to understand the messages of this report.
My purpose is to urge all decision-makers – in government, industry and the community – to listen to the science.
Focus on the goal
It would be possible for the public to take from this week’s headlines an overwhelming sense of despair.
The message I take is that we do not have time for fatalism.
We have to look squarely at the goal of a zero-emissions planet, then work out how to get there while maximising our economic growth. It requires an orderly transition, and that transition will have to be managed over several decades.
That is why my review of the National Electricity Market called for a whole-of-economy emissions reduction strategy for 2050, to be in place by the end of 2020.
The Finkel Review at a glance
We have to be upfront with the community about the magnitude of the task. In a word, it is huge.
Many of the technologies in the IPCC’s most optimistic scenarios are at an early stage, or conceptual. Two that stand out in that category are:
carbon dioxide removal (CDR): large-scale technologies to remove carbon dioxide from the atmosphere.
carbon capture and sequestration (CCS): technology to capture and store carbon dioxide from electricity generation.
It will take a decade or more for these technologies to be developed to the point at which they have proven impact, then more decades to be widely deployed.
The IPCC’s pathways for rapid emissions reduction also include a substantial role for behavioural change. Behavioural change is with us always, but it is incremental.
Driving change of this magnitude, across all societies, in fundamental matters like the homes we build and the foods we eat, will only succeed if we give it time – and avoid the inevitable backlash from pushing too fast.
The IPCC has made it clear that the level of emissions reduction we can achieve in the next decade will be crucial. So we cannot afford to wait.
No option should be ruled off the table without rigorous consideration.
In that context, the Finkel Review pointed to a crucial role for natural gas, particularly in the next vital decade, as we scale up renewable energy.
The IPCC has made the same point, not just for Australia but for the world.
The question should not be “renewables or coal”. The focus should be on atmospheric greenhouse emissions. This is the outcome that matters.
Denying ourselves options makes it harder, not easier, to get to the goal.
There also has to be serious consideration of other options modelled by the IPCC, including biofuels, catchment hydroelectricity, and nuclear power.
My own focus in recent months has been on the potential for clean hydrogen, the newest entrant to the world’s energy markets.
In future, I expect hydrogen to be used as an alternative to fossil fuels to power long-distance travel for cars, trucks, trains and ships; for heating buildings; for electricity storage; and, in some countries, for electricity generation.
We have in Australia the abundant resources required to produce clean hydrogen for the global market at a competitive price, on either of the two viable pathways: splitting water using solar and wind electricity, or deriving hydrogen from natural gas and coal in combination with carbon capture and sequestration.
Building an export hydrogen industry will be a major undertaking. But it will also bring jobs and infrastructure development, largely in regional communities, for decades.
So the scale of the task is all the more reason to press on today – at the same time as we press on with mining lithium for batteries, clearing the path for electric vehicles, planning more carbon-efficient cities, and so much more.
There are no easy answers. I hope, through this and other reports, there are newly determined people ready to contribute to the global good.
Australia has never been a stranger to droughts, but climate change is now super-charging them.
Besides taking a toll on human health, droughts also bake the earth. This means the ground holds less water, creating a vicious cycle of dryness.
Our research has investigated ways to improve the health and structure of soil so it can hold more water, even during droughts. It’s vital to help farmers safeguard their soil as we adapt to an increasingly drought-prone climate.
Soil moisture is key
The immediate effect of drought is complete loss of soil water. Low moisture reduces soil health and productivity, and increases the loss of fertile top soil through wind and water erosion.
To describe how we can improve soil health, we first need to explain some technical aspects of soil moisture.
Soil moisture is dictated by three factors: the ability of the soil to absorb water; its capacity to store that water; and the speed at which the water is lost through evaporation and runoff, or used by growing plants.
These three factors are primarily determined by the proportions of sand, silt and clay; together these create the “soil structure”. The right mixture means there are plenty of “pores” – small open spaces in the soil.
Soils dominated by very small “micropores” (30-75 micrometres), such as clay soil, tend to store more water than those dominated by macropores (more than 75 micrometers), such as sandy soil.
If the balance is skewed, soil can actually repel water, increasing runoff. This is a major concern in Australia, especially in some areas of Western Australia and South Australia.
Improving soil structure
Good soil structure essentially means it can hold more water for longer (other factors include compaction and surface crust).
Farmers can improve soil structure by using minimum tillage, crop rotation and return of crop residues after harvest.
Another important part of the puzzle is the amount of organic matter in the soil –it breaks down into carbon and nutrients, which is essential for absorbing and storing water.
There are three basic ways to increase the amount of organic matter a given area:
grow more plants in that spot, and leave the crop and root residue after harvest
slow down decomposition by tilling less and generally not disturbing the soil more than absolutely necessary
apply external organic matter through compost, mulch, biochar and biosolids (treated sewage sludge).
Typically, biosolids are used to give nutrients to the soil, but we researched its impact on carbon storage as well. When we visited a young farmer in Orange, NSW, he showed us two sites: one with biosolids, and one without. The site with biosolids grew a bumper crop of maize the farmer could use as fodder for his cattle; the field without it was stunted.
The farmer told us the extra carbon had captured more moisture, which meant strong seedling growth and a useful crop.
This illustrates the value of biowastes including compost, manure, crop residues and biosolids in capturing and retaining moisture for crop growth, reducing the impact of drought on soil health and productivity.
Improving soil health cannot happen overnight, and it’s difficult to achieve while in midst of a drought. But how farmers manage their soil in the good times can help prepare them for managing the impacts of the next drought when it invariably comes.
The author would like to thank Dr Michael Crawford, CEO of Soil CRC, for his substantial contribution to this article.
A landmark report from the Intergovernmental Panel on Climate Change, commissioned at the breakthrough 2015 summit that brokered the Paris climate agreement, outlines what’s at stake in the world’s bid to limit global temperature rise to 1.5℃.
The report, released today, sets out the key practical differences between the Paris agreement’s two contrasting goals: to limit the increase of human-induced global warming to well below 2℃, and to “pursue efforts” to limit warming to 1.5℃.
Two and a half years in the making, the report provides vital information about whether the Paris Agreement’s more ambitious goal is indeed achievable, what the future may look like under it, and the risks and rewards of hitting the target.
Here are five key questions to which the report provides answers.
Can we limit warming to 1.5℃?
There is no clear yes or no answer to this question.
Put simply, it is not impossible that global warming could be limited to 1.5℃. But achieving this will be profoundly challenging.
If we are to limit warming to 1.5℃, we must reduce carbon dioxide emissions by 45% by 2030, reaching near-zero by around 2050.
Whether we are successful primarily depends on the rate at which government and non-state bodies take action to reduce emissions. Yet despite the urgency, current national pledges under the Paris Agreement are not enough to remain within a 3℃ temperature limit, let alone 1.5℃.
Global warming is not just a problem for the future. The impacts are already being felt around the world, with declines in crop yields, biodiversity, coral reefs, and Arctic sea ice, and increases in heatwaves and heavy rainfall. Sea levels have risen by 40.5mm in the past decade and are predicted to continue rising for decades, even if all greenhouse emissions were reduced to zero immediately. Climate adaptation is already needed and will be increasingly so at 1.5℃ and 2℃ of warming.
Rapid action is essential and the next ten years will be crucial. In 2017, global warming breached 1℃. If the planet continues to warm at the current rate of 0.2℃ per decade, we will reach 1.5℃ of warming around 2040. At current emissions rates, within the next 10 to 14 years there is a 2/3 chance we will have used up our entire carbon budget for keeping to 1.5.
How can we limit warming to 1.5℃?
The report says “transformational” change will be needed to limit warming to 1.5℃. Business as usual will not get us there.
Global emissions of carbon dioxide, methane and other greenhouse gases need to reach net zero globally by around 2050. Most economists say putting a price on emissions is the most efficient way to do this.
By 2050, 70-85% of electricity globally will need to be supplied by renewables. Investment in low-carbon and energy-efficient technologies will need to double, whereas investment in fossil-fuel extraction will need to decrease by around a quarter.
Carbon dioxide removal technology will also be needed to remove greenhouse gases from the atmosphere. But the IPCC’s report warns that relying too heavily on this technology would be a major risk as it has not been used on such a large scale before. Carbon dioxide removal is an extra step that may be needed to keep warming to 1.5℃, not an excuse to keep emitting greenhouse gases.
Production, consumption and lifestyle choices also play a role. Reducing energy demand and food waste, improving the efficiency of food production, and choosing foods and goods with lower emissions and land use requirements will contribute significantly.
Taking such action as soon as possible will be hugely beneficial. The earlier we start, the more time we have to reach net zero emissions. Acting early will mean a smoother transition and less net cost overall. Delay will lead to more haste, higher costs, and a harder landing.
Reducing emissions quickly will also ensure warming is capped as soon as possible, reducing the number and severity of impacts.
Yet severe impacts will still be experienced even if warming is successfully capped at 1.5℃.
What is the cost of 1.5℃ of warming?
Although the Paris Agreement aims to hold global warming as close to 1.5℃ as possible, that doesn’t mean it is a “safe” level. Communities and ecosystems around the world have already suffered significant impacts from the 1℃ of warming so far, and the effects at 1.5℃ will be harsher still.
Poverty and disadvantages will increase as temperatures rise to 1.5℃. Small island states, deltas and low-lying coasts are particularly vulnerable, with increased risk of flooding, and threats to freshwater supplies, infrastructure, and livelihoods.
Warming to 1.5℃ also poses a risk to global economic growth, with the tropics and southern subtropics potentially being hit hardest. Extreme weather events such as floods, heatwaves, and droughts will become more frequent, severe, and widespread, with attendant costs in terms of health care, infrastructure, and disaster response.
The oceans will also suffer in a 1.5℃ warmer world. Ocean warming and acidification are expected to impact fisheries and aquaculture, as well as many marine species and ecosystems.
Up to 90% of warm water coral reefs are predicted to disappear when global warming reaches 1.5℃. That would be a dire situation, but far less serious than at 2℃, when the destruction of coral reefs would be almost total (greater than 99% destruction).
How do 1.5℃ and 2℃ compare?
Impacts on both human and natural systems would be very different at 1.5℃ rather than 2℃ of warming. For example, limiting warming to 1.5℃ would roughly halve the number of people globally who are expected to suffer from water scarcity.
Seas would rise by an extra 10cm this century at 2℃ compared with 1.5℃. This means limiting global warming to 1.5℃ would save up to 10.4 million people from the impacts of rising seas.
At 1.5℃ rather than 2℃:
up to 427 million fewer people will suffer food and water insecurity, climate risks, and adverse health impacts
extreme weather events, heat-related death and disease, desertification, and wildlife extinctions will all be reduced
it will be significantly easier to achieve many of the United Nations’ Sustainable Development Goals, including those linked to hunger, poverty, water and sanitation, health, and cities and ecosystems.
How does the 1.5℃ target fit with the Sustainable Development Goals?
The Sustainable Development Goals aim for a world in which people can be healthy, financially stable, well fed, have clean air and water, and live in a secure and pleasant environment. Much of this is consistent with the goal of capping global warming at 1.5℃, which is why the IPCC notes there are synergies if the SDG initiatives and climate action should be explicitly linked.
But some climate strategies may make it harder to achieve particular SDGs. Countries that are highly dependent on fossil fuels for employment and revenue may suffer economically in the transition towards low-carbon energy.
Carefully managing this transition by simultaneously focusing on reducing poverty and promoting equity in decision-making may help avoid the worst effects of such trade-offs. What works in one place may not work in another, so strategies should always be locally appropriate.
Limiting global warming to 1.5℃ will require a social transformation, as the world takes rapid action to reduce greenhouse gases. The effects of climate change will continue to shape the world we live in, but there is no doubt we will be far better off under 1.5℃ than 2℃ of global warming.
The choices we make today are shaping the future for coming generations. As the new report makes clear, if we are serious about the 1.5℃ target, we need to act now.
The authors gratefully acknowledge the substantial contribution to authorship of this article by of Lamis Kazak, an Australian National University Bachelor of Interdisciplinary Studies (Sustainability) student, as part of a Science Communication Internship with the Climate Change Institute.