Curious Climate schools
Curious Climate schools

Dr Gabi Mocatta

Affiliation
Climate Futures, School of Geography, Planning, and Spatial Sciences, University of Tasmania & Deakin University
Research Areas
Climate change communication, climate science translation and climate literacy
Why I do what I do
I want to be part of the solution that is so urgently needed to the climate problems we all face.
Something interesting about me
I've run ultramarathons. My longest: 85kms in a day. Great fun!

Questions answered by this expert

How long have we ignored the science of climate change?
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We’ve known about climate change and what causes it for a long time.

In fact, the first experimental observations of the effects of greenhouse gases were made by a female scientist, Eunice Foote, in 1856. In that year, she gave a talk at an American science meeting in which she described how glass jars containing different concentrations of water vapour, carbon dioxide and air heated up at different rates in the sun. Her research brought her to speculate that higher concentrations of carbon dioxide in the air could influence global temperatures.

Eunice Foote - the first person to describe the warming effects of carbon dioxide concentrations.

Despite Eunice Foote’s discoveries Irish physicist, John Tyndall, is generally given the credit for first describing the 'Greenhouse Effect', in 1859. He published a series of studies showing how greenhouse gases such as carbon dioxide trapped heat in the Earth’s atmosphere.

In the 1950s and 1960s, scientists were developing a better understanding of what might be ahead of us in terms of climate change. Nobel Prize winning chemist, Glenn T. Seaborg warned in 1966 of a looming crisis, saying: "At the rate we are currently adding carbon dioxide to our atmosphere (six billion tons a year), within the next few decades the heat balance of the atmosphere could be altered enough to produce marked changes in the climate - changes which we might have no means of controlling”. In the 1950s, the New York Times reported that more carbon dioxide in the atmosphere “generated by man” was warming the climate.

In the 1970s the first global climate models were developed. They showed that it was impossible to increase carbon dioxide in the earth’s atmosphere and not have a global rise in temperature. In the 1980s, drilling ice cores deep into the Greenland and Antarctic ice allowed scientists to study bubbles of ancient air trapped there for thousands of years. This showed scientists that carbon dioxide concentrations in the Earth's atmosphere were historically much lower. This information helped confirm a remarkably consistent relationship between carbon dioxide in the atmosphere and Earth’s temperature.

In 1988, NASA scientist, James Hansen famously testified to the US Congress that “the greenhouse effect is here” and that “global warming has begun”. That same year, the Intergovernmental Panel on Climate Change (IPCC) was formed by the United Nations Environment Programme and the World Meteorological Organisation to study and report on climate change and its solutions. The IPCC and its thousands of scientists have since written numerous detailed reports on climate change, its impacts, and possible solutions. In 2007 it was awarded the Nobel Peace Prize for “efforts to build up and disseminate greater knowledge of man-made climate change, and to lay the foundations for the measures that are needed to counteract such change”. Today, more than 99% of scientists agree that global warming is anthropogenic – that is, caused by humans.

This short video describes how James Hansen's testimony on climate change was right.

Despite centuries of science and decades of increasing evidence on the causes and consequences of climate change, plus growing consensus on the actions needed to mitigate it, there is one clear and crucial piece of evidence on the way humans have not dealt with the problem - and that is how carbon dioxide levels in the atmosphere keep rising. Carbon dioxide in the atmosphere was around 280 parts per million (ppm) in pre-industrial times (before we started burning a lot of fossil fuels). Today they are 420 ppm, and climbing.

This graph shows atmospheric carbon dioxide concentrations over 800,000 years.
The current amount is slightly higher than shown here. (Source: NASA)

This is not to say that we have ignored the science of climate change entirely. Some really important landmark decisions have been made on the strength of climate science – for example, the 2015 Paris Agreement where countries agreed to keep global temperature rise to no more than 2°C and to make the best efforts to keep it below 1.5°C. Climate scientists have been increasingly been sounding the alarm on the consequences of inaction. The IPCC’s Sixth Assessment report is the clearest yet on physical science behind climate change and warns of the severe consequences of not drastically cutting greenhouse gases this decade. The UN COP26 Climate Conference in Glasgow is now a crucial opportunity for policy makers to show they can finally take transformational action based on our very clear scientific understanding of climate change.

Given the potentially harmful emissions – is the burning of waste for electricity generation considered sustainable practice?
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This is an excellent question. Australia produces an astounding 70 million tonnes of waste annually and we need to deal with all this rubbish we create. In terms of plastic alone, in 2017-2018, some 3.4 million tonnes of plastic were used in Australia. Of that just 320,000 tonnes (only 9.4%) were recycled.

Historically, most of our waste has gone to landfill. About half of the waste we currently produce is able to be recycled, but Australia has recently seen a problematic breakdown in its recycling systems. We have partly dealt with the problem in recent years by shipping recyclables offshore to countries like China and Malaysia for processing. While dumping our rubbish in other countries is far from acceptable, shipping a “high quality” waste stream of recyclable material for effective processing and re-use is one way to make our global economy more circular. In 2018, though, China banned waste imports from Australia, and then in late 2020, Australia prohibited sending its own unprocessed waste overseas, partly to stimulate recycling systems in Australia.

A loading bay at a waste to energy facility in the USA. (Source: Climate Visuals).

Given we have so much waste to deal with, and only part of it can be recycled, much of the rest ends up in landfills. This is a problem in relation to climate change. Organic waste in landfills produces the greenhouse gas methane. Some landfills collect this for energy generation – not all – and the rest ends up in the atmosphere as a potent climate heating gas.

So could burning some of our waste be a better way to deal with it if it also produces energy from non-recyclable waste that would otherwise be sent to landfill? In terms of carbon accounting, waste-to-energy plants may potentially reduce greenhouse gas emissions. Australia’s biggest waste-to-energy plant at Kwinana in WA says it allows 486,000 tonnes of carbon dioxide emissions to be avoided each year. Australia now has two recently built state-of-the-art waste to energy plants, both in Western Australia. These plants emulate a technology that is becoming increasingly common in Europe and, if they are powered by material that is considered renewable – as designed to do – then they are considered by the Australian Renewable Energy Agency (ARENA) as a form of renewable energy. The ash which is the byproduct of this incineration process can be re-used, for example, in road building.

Construction of the Kwinana waste-to-energy facility in WA. (Source: ARENA)

Despite being what sounds like a good solution to dealing with waste, incinerating rubbish is not without problems. There are certainly toxic chemicals associated with the process. Just one example, dioxins, a highly toxic and persistent organic pollutant, have been found in higher concentrations around waste incinerators. Above all, waste-to-energy plants ultimately also undermine a circular economy: they need us to keep producing large amounts of waste to keep going. If we are truly going to deal with waste in the most sustainable way, we need to produce less of it, and keep recycling materials. Needing waste to burn supports the continued production of waste, and ultimately, that’s not good for the planet. Overall, then, it's not a very sustainable practice - but it may have a use for some kinds of waste and in some places.

Are there effective ways to mitigate the production of emissions associated with renewable energy production and fossil fuel consumption?
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This is such a good question, as it shows you are thinking about that fact that all sources of energy, whether renewable or non-renewable (like fossil fuels) have some emissions associated with them.

We all know well that fossil fuels are a real problem because of the large amounts of greenhouse gases they emit when burned. We can turn to renewable energy as an alternative – things like solar, wind and hydro. However, these technologies also have some carbon emissions associated with them. For example, if we think of a wind turbine, while the power it generates is low carbon, it’s not zero carbon. Carbon dioxide emissions are generated throughout a wind turbine’s life cycle, from mining the raw materials to build it, to its manufacture, construction, maintenance and also decommissioning at the end of the turbine’s “life”.

Wind turbines under construction

Did you know hydroelectric dams, particularly in tropical areas, can also have significant methane emissions associated with them, due to vegetation rotting under the dam’s water for several years after dams are first flooded? Methane is a powerful greenhouse gas, meaning that even hydroelectricity isn’t entirely “emissions free”.

Though no energy source is “perfect” in terms of carbon emissions, the carbon emissions associated with renewable energy sources over their life cycles are much, much lower than emissions from burning fossil fuels. In the near future, we may be able manufacture things like the steel for wind turbines not using fossil fuel but instead, using green hydrogen, making life cycle emissions of renewable energy sources even lower.

You asked about mitigating emissions from all energy sources: this is where the role of carbon sinks and offsets comes in. Even when we reach “net zero”, there will still be some emissions. Net zero means achieving an overall balance between greenhouse gas emissions produced, and greenhouse gas emissions taken out of the atmosphere, for example by trees and natural environments. When we are able to achieve that balance, then we will be doing really well – so that energy we consume in our daily lives won’t have a detrimental effect on our atmosphere and on the planet.

How can we educate the older people so they understand what is happening with climate change?
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How can we stop climate change from happening, and are there more ways than one?
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How do we make everyone aware of what we are doing to the earth and spread the message that we need to change our ways?
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Is nuclear power a viable alternative to present energy production to cut down greenhouse gas emissions?
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What an excellent and timely question: there has been a lot of discussion about nuclear power in the media recently. Also, Australia’s new plan to get to net zero emissions by 2050 does not rule out including nuclear power in this country’s future energy mix. So it’s an important time to be thinking and talking about nuclear.

Nuclear energy is used to generate electricity in 30 countries around the world, and provides about a tenth of the world’s energy needs. Nuclear power needs uranium, and the planet has uranium resources sufficient to fuel existing demand for more than 130 years. Nuclear power does not cause direct greenhouse gas emissions, which is good when we are thinking about climate change, however, the waste from nuclear power generation is problematic. It remains radioactive potentially for thousands of years and needs to be carefully stored under very controlled conditions in order not to pose a danger to humans and the environment.

Could Australia develop nuclear power? Currently the answer is no. That’s because Australian law currently prohibits the approval and construction of nuclear power plants and the enrichment of uranium needed for nuclear power. Could Australia develop nuclear power in the future as part of an effort to reduce greenhouse gas emissions? Australia does have a lot of uranium, in fact, it supplies about one third of the total world demand for uranium.

Australia's uranium resources (Source: Geoscience Australia)

The problem with nuclear for Australia as part of the effort to reduce emissions this decade is quite simple: it’s too slow, and too expensive.

How is it too slow? The timeframe to build a nuclear power station is at least 10-12 years. If we started to build a nuclear power capacity in Australia right now (and remember, the law  currently prohibits it) it would not be operational until the early-mid 2030s. Science tells us we need to cut emissions right now, this decade.

How is it too expensive? Despite our domestic reserves of uranium, nuclear is by far the most costly energy for Australia to generate, as you can see from the illustration below.




Comparison of power generation technology cost estimates. Source: CSIRO Gen Cost 2019-2020

If we were to build nuclear power capacity in Australia, starting today, the cost of renewables like wind and solar would be much less even than it is today by the time we were able to generate any nuclear power.

So we might pursue building nuclear power in Australia if we had no other alternatives, but we are lucky to have some of the most plentiful solar, wind and particularly offshore wind resources in the world. So renewables like wind and solar, backed up by hydroelectricity, batteries, and new fuels like green hydrogen, will be a faster and cheaper way to decarbonise than turning to nuclear power.

Would switching our power sources from fossil fuels to renewable energy have any short or long side effects on the way we live and how the economy works? (Availability, Unemployment Rate, Things that rely on fossil fuels, stuff like that.)
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This is an excellent question and there are many possible answers. As you know, climate change itself can be described as a “wicked problem” for which there is no one “correct” solution.

It’s certainly possible to switch power sources from fossil fuels to renewable energy – especially wind and solar – and with the right incentives and policy from government. Importantly, we can do so quite quickly which is exactly what is now needed. We can do this both on a small scale (eg: solar panels on rooftops) to a larger scale (eg: vast solar and wind farms). In Australia, we are particularly lucky to have excellent conditions for generating renewable power: plenty of sun and wind, and space for solar and wind farms.

We can also use wind and solar, and also existing hydroelectric energy generation, to help manufacture what’s known as “green” hydrogen as an emissions-free fuel. Making hydrogen needs lots of electricity, but if we use electricity from fossil fuels in this process, we don’t cut carbon dioxide emissions enough. Creating a green hydrogen industry is a really exciting opportunity, especially for Tasmania, as we may be able to export hydrogen to replace fossil fuels in manufacturing and heavy transport industry. For example, it’s currently being used in mining trucks instead of diesel. Take a look at this short video to help you understand more about green hydrogen.

You asked about side effects. One very positive side effect is that switching from fossil fuels to renewables will actually create jobs in Australia. Renewable energy could employ as many as 44,000 Australian workers by 2025. Of course, people who currently work in the fossil fuels industries would need to transition jobs, and this would need to be done in such a way that is fair to those workers. Some reports forecast that there could be 250,000 additional jobs in Australia by 2070 if the transition to a renewable economy is managed well.

Another positive side effect of moving away from fossil fuels will be cleaner air. Burning fossil fuels produces carbon dioxide, which is bad for the climate, but also produces pollutants such as sulphur dioxide, nitrogen dioxide and very fine particles which can play havoc with our respiratory and cardiovascular systems. A recent study showed that Australia could save $6 billion a year on health costs if we stopped burning fossil fuels.

In terms of negative side effects, one important one is that our transition to a renewable energy future will still have significant environmental impacts. Vast wind turbines need huge amounts of steel and copper, solar panels need rare earth minerals and batteries need lithium. All of these need to be mined from the earth, often with extremely damaging environmental consequences and impacts on biodiversity. So we need to remember that all consumption, even renewable energy consumption, has an impact on our planet. If we can consume less – particularly those of us in developed countries  –  and move towards a circular economy where what we extract from the earth is used and re-used, our transition to a decarbonised world will also mean a healthier and fairer environment for all.

How will society have to adapt to climate change?
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It’s important firstly to distinguish between mitigation and adaptation when we are talking about climate change. Mitigation means all those actions intended to lessen climate change, mainly by reducing greenhouse gas emissions and enhancing nature’s ability to absorb emissions. Mitigation includes things like transforming our energy, transport and manufacturing systems so that we can move away from fossil fuels. It also includes helping nature to recover with tree planting and habitat restoration so that natural environments can help us do the work of reaching net zero emissions by absorbing carbon dioxide. However, even if we can cut global emissions in half by 2030 and reach net zero emissions by 2050 – the key goal of the 2015 Paris Agreement – impacts of climate change will continue to be felt for some time. We will therefore need to work on adaptation: that is, changing our societies to better cope with the impacts of climate change already being felt and the impacts projected into the future.

One of the key things we need to think about is adapting to sea level rise. Scientists from the Intergovernmental Panel on Climate Change (IPCC) tell us even if we succeed in strongly reducing emissions, greenhouse gases already in the atmosphere and heating already in the climate system will mean that sea levels continue to rise for centuries. Sea levels could rise by 30-60cms by 2100, even if global warming is kept below 2°. Seas could rise as much as 60-110cm by 2100 if we don’t curb emissions strongly. In any future emissions scenario, therefore, coastal areas and low lying land areas will have to adapt to saltwater flooding from sea level rise. In some cases this may mean building extensive sea walls: such adaptation infrastructure is now being considered by low-lying cities, for example Miami in Florida, USA. In other places, like low-lying Pacific Islands, this may be less feasible and moving away from such islands may be a necessary adaptation action. For example, people living on the Carteret Islands in Papua New Guinea are already having to decide to leave their islands, as sea levels rise.

Increasing heat will also call for adaptions. Heatwaves are Australia’s most dangerous extreme weather risk for humans. Heatwaves are becoming hotter, lasting longer and occurring more often. By mid-century in Australia, we expect to see an increasing number of days on which there is severe heat danger for people working outside. Outdoor work normally done in the daytime may need to be undertaken at night (eg: agricultural work). Architecture of homes to allow more natural cooling and of cities to reduce the urban heat island effect with planting of more trees are possible adaptations.

In a heating world, we will also need to be better prepared for bushfires – particularly in Australia. This may mean further upgrading of building codes to make every house in bushfire-prone areas more bushfire ready. Though we can better protect houses by clearing vegetation around them, houses in some areas may not be able to be adequately protected from fire. This could mean that one climate change adaptation we may see in the future is whole communities needing to move out of particularly bushfire-prone areas.

Some impacts of climate change may allow for potentially positive adaptations. For example, in Tasmania, overall warming may allow for a change of land use choices in agriculture, with potentially higher economic returns. Climate modelling for Tasmania shows that by 2085, pasture production of ryegrass for livestock could increase in some areas by 10-100% due to an earlier start to spring and therefore a longer growing season. Wheat cropping in some parts of Tasmania could see a 10-15% increase in yields. However, agricultural pests (eg: fruit fly) could become a problem for agriculture in a warmer Tasmania. Farmers will therefore need to adapt on several levels.

How does climate change impact the Earth apart from the weather?
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Climate change affects the earth in many and complex ways. Much research attention is currently being directed towards the influence of climate change on biodiversity both on land and in the oceans.

You’ve likely seen discussion about coral bleaching on our own Great Barrier Reef. Research from the IPCC (Intergovernmental Panel on Climate Change) shows that with global temperature rise of 1.5°C, 70-90% of coral reefs will be lost. With a rise of 2°C, 99% percent will be lost. Along with coral loss will come the degradation or loss of whole reef ecosystems and the species evolved to live in them.

The oceans have absorbed around a third to a half of carbon dioxide released into the atmosphere through human activity since the 1850s. This process is changing the pH of ocean water, making it more acidic. Research shows that there has been a 26% increase in ocean acidity since the 1850s – which is about 10 times faster than at any time in the last 55 million years. Ocean acidification makes carbonate less available in sea water and as this is the building block of the shells and skeletons of many marine organisms, it has negative consequences for many marine organisms. Molluscs and some species of plankton are particularly affected. Ocean acidification also further weakens coral, making it more vulnerable to destruction in storms. Some species may benefit: some algae and sea grasses may increase their growth rates. This image summarises how some key marine organisms will likely be impacted:

Effects of ocean acidification on marine life. Source: Adapted from Kroeker et al. 2013.

                                                 

On land, climate change impacts on ecosystems are already widespread. One of the most visible may be the loss of millions of hectares of pine forest in British Colombia in Canada since the 1990s. This widespread damage has been caused by an insect called the Mountain pine beetle (Dendroctonous ponderosae). Normally kept in check by cold winter temperatures, the beetle has been able to survive winters that have recently become warmer due to climate change and has killed trees across vast areas.

In other places, species that are adapted to cool alpine or temperate environments move up towards mountaintops as temperatures warm – however, when they reach mountain summits, there is nowhere else for them to go. One example of this is the White lemuroid ringtail possum (Hemibelideus lemuroides) which lives only in the high altitude Daintree cloud forests here in Australia and is now only found on a few isolated mountain tops. It’s unable to survive temperatures above 30°C for very long.

Of course, animals that rely on ice, for example, Polar bears and Ringed seals in the Arctic, and Emperor penguins in the Antarctic, will be increasingly threatened as ice melts. A recent study has warned that almost all Emperor penguins in Antarctica will die out if no changes are made to greenhouse gas emissions.

The situation for the planet’s biodiversity is certainly very precarious and confronting – however, these losses are not inevitable. Science tells us that if we can work globally to limit greenhouse gas emissions quickly and dramatically, we would see a stabilisation of temperatures within 20-30 years. Restoring natural habitats has been identified as one way to both protect biodiversity and store carbon – a win-win for local biodiversity and the planet as a whole. Reducing emissions and restoring habitats (sometimes called “rewilding”) are essential now to protect the remarkable biodiversity of planet Earth.  

Which place in the world is climate change affecting most?
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There have been quite a few questions asking which countries and which places in the world are most affected by climate change, and about which countries are getting hotter, quicker.

As you know, the effects of climate change are different everywhere. Overall, we are seeing the planet heating, but this has different impacts in different places.

Did you know that climate change is also affecting where rain falls? How windy it is? When and where cyclones occur? There is nowhere on Earth that climate change isn’t having an impact, but the ways that climate change affects different countries depends on lots of different factors, including their geographical location, their exposure to different types of change, the sensitivity of the environment to change, and the capacity of their human population to adapt. 

Understanding which is the most affected country depends on the risk criteria you are looking at.

If you wanted to know where the highest number of people are affected by climate change right now, you might think of countries affected by more intense extreme weather events, like Pakistan, Haiti, and the Philippines.

Also greatly impacted are countries with large cities in south-east Asia like Indonesia, and Bangladesh, which are losing coastal land with sea level rise, or countries in Africa affected by drought, like Kenya. If you wanted to know which countries are being faced with becoming unliveable or being lost altogether, you might think of countries in the Middle East reaching 50°C more often, or low-lying islands like Tuvalu, the Torres Strait Islands, and the Maldives. 

Walking through flood water in Jakarta, Indonesia

In Bangladesh, salt water flooding over land has made farming impossible in many areas and finding fresh drinking water challenging.

In other parts of the world, the effects of climate change will be most felt by millions of people in terms of access to water. Many countries rely on water from glacier and snow melt both for drinking water and for agriculture. Countries like the Andean nations especially Peru, Chile, Bolivia, and countries in Southeast Asia that rely on glacier meltwater from the Himalayas could be strongly affected, as glacier ice is now melting faster than ever and less snow is tending to fall in some places – meaning there will be less water available in the long term.

Of course, parts of the planet that are already hot will become much more difficult to live in as it becomes hotter. Tropical areas around the Equator are most at risk here. Tropical areas could be pushed towards the limits of what humans can survive if temperatures rise more than 1.5°C above preindustrial levels. Humans can tolerate dry heat better than they can humid heat. Humans are unable to tolerate what is called a “wet bulb temperature” (that’s a measure of heat and humidity together) of over 35°C for very long. In these conditions, the human body is not able to cool itself down by sweating and such conditions can be fatal. Such conditions may have dire consequences for many animals as well. With temperatures increasing everywhere, this could have very serious consequences as about 40% of the world’s population currently lives in tropical areas. This effect of climate change alone could cause a huge refugee crisis with potentially millions of people displaced by climate change by 2050.

Just in terms of temperature rise, perhaps surprisingly, some of the coldest areas have warmed the most due to climate change. Though the global average temperature rise is currently at 1.1°C above preindustrial levels (and Australia’s average temperate is currently  1.44°C higher than when records began) the Arctic is heating up much more dramatically. Between 1971 and 2019, the Arctic’s average annual temperature rose by 3.1°C, meaning it’s heating almost three times faster than the rest of the planet – with drastic consequences on Arctic ecosystems and Indigenous peoples who call the Arctic home. The following video can help us to visualise which parts of the world have heated up most over the past 140 years, and therefore helps us understand which areas are currently most affected by climate change

While some countries might be worse off than others, and some countries might have more capacity to do something to limit the impacts, climate change is affecting ALL OF US and we all have a responsibility to make a positive difference.

What are the main things we need to know about climate change?
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The main things we need to know about climate change are actually quite straightforward. We need to know that:

We have linked the points above to other answers from the Curious Climate Schools experts so you can read more.

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