Global Warming: Facts and Ethics (by Ian B. Lambert, Australia)
By Ian B. Lambert
Earth scientist, Australia. E-mail: scottie8148@gmail.com
Ph.D. in geochemistry from the Australian National University. After post-doctoral research at University of Chicago, he joined CSIRO where he rose to Principal Research Scientist, before joining Australia’s federal government, where he led groups providing scientific advice on resources, energy, and environmental issues. He was Secretary General of the 34th International Geological Congress (IGC) and the International Union of Geological Sciences (IUGS).
1. INTRODUCTION
There is widespread acceptance that Earth’s climate is warming, but there is disagreement about why this is happening, and what needs to be done about it.
The UN's International Panel on Climate Change (IPCC) has concluded that:
current warming is predominantly the result of increasing levels of greenhouse gases (GHG) in the atmosphere from burning fossil fuels,
if the global average surface temperature rises more than ca. 1.5°C to 2°C above the pre-industrial level, major and potentially irreversible changes to climate systems are likely, and
rapid global decarbonisation is necessary to minimises threats to Earth systems and humanity.
However, influential climate sceptics/deniers with strongly held views have caused uncertainties by actively arguing that decarbonisation is unnecessary, or at least not urgent. Some sceptics are well-meaning and believe we are going through a natural warming event like the many recorded in the geological past, so they maintain there is not much we can do about it. Deniers, including many fossil fuel industry supporters and political conservatives are opposed to taking actions that could affect their vested interests, and/or have extremely high costs.
This article, which is written for a lay audience and from an Australian perspective, outlines and evaluates the key issues with the aim of clearing up uncertainties about the cause of the current warming and the case for climate action. It:
outlines key scientific evidence behind the IPCC’s findings;
summarises what decarbonisation entails;
discusses concerns about availability of sufficient critical minerals to achieve timely global decarbonisation; and
evaluates the claims made by sceptics/deniers, and the ethical considerations they raise.
2. SCIENTIFIC EVIDENCE FOR EXISTENTIAL THREATS FROM CLIMATE CHANGE
Earth is the only body in the universe that is known to have an atmosphere capable of supporting complex carbon-based life. Greenhouse gases, particularly carbon dioxide (CO2), provide carbon for growth of life-forms, and control surface temperatures by trapping solar heat in the atmosphere.
Therefore, it is vital that Earth’s delicately balanced greenhouse system is not disrupted. With that in mind, it is concerning that atmospheric CO2 levels have risen by around 50 percent over the past century (Fig. 1), and this has been accompanied by average global terrestrial and marine summer temperatures increasing to the highest recorded levels. Yesterday’s climate extremes are today’s normal.
The visible consequences include accelerating melting of polar and glacial ice and pernafrost, rising sea levels, warmer and more acidic oceans, more intense heatwaves, and changing patterns of droughts, bushfires, storms, and floods. These are already affecting economies, public health, infrastructure, and ecosystems.
The IPCC’s conclusions are based on extensive scientific studies and climate modelling by international experts, which have been published in its reports. These are the basis for setting the 2015 Paris Agreement target tor achieving net zero by 2050 – that is, a balance between GHG added to and removed from the atmosphere by mid-century. Almost all countries are signatories to the 2015 Paris Agreement but, unfortunately, the seriousness of their endeavours to minimise GHGs vary considerably.
2.1 What past climate changes tell us about current trends
Studies of the geological record indicate there have been repeated climate change events, with extremely hot and frozen periods, and associated major sea level fluctuations. While the causes of past natural global climate change events varied in detail, the evidence points to the fundamental driver being the levels of atmospheric CO2, from organic and inorganic sources.
The organic carbon cycle involves growth and decomposition of life forms, including photosynthesis and burial of organic remains in sediments (potentially generating fossil fuels). Simple single-cell organisms evolved soon after the Earth formed, some 4.6 billion years ago, and complex life forms evolved around 600 million years ago.
The inorganic carbon cycle involved build up of atmospheric CO2 from sustained elevated levels of volcanic activity, and decreasing CO2 levels from rock weathering and formation of sedimentary carbonate strata.
Detailed studies of geological strata globally show that substantial changes in past atmospheric CO2 levels and climates occurred over periods of many thousands of years. These were associated with major events, including the evolution of new lifeforms (for example, land plants), periods of major volcanic activity, overturning of layered oceans with organic-rich bottom waters, and formation of thick sequences of limestone strata.
An interesting case study is the end-Permian extinction, around 250 million years ago, which wiped out 95 percent of all life. Detailed studies have linked this to a prolonged period of intense volcanic activity (the Siberian Traps), which released vast amounts of CO2 plus sulphur (greenhouse) gases. Temperatures increased by some 5oC and, ocean waters were depleted of their oxygen as hydrogen sulphide built up. The increased temperatures resulted in melting of methane hydrate in sea-bottom strata and permafrost, releasing methane to the atmosphere. Although methane is a powerful greenhouse gas, it only survives for about 12 years in the atmosphere. However, it was emitted for a protracted period and caused further temperature increases. All of this happened over a period of around 100,000 years and left only vestiges of life on a devastated Earth.
The end-Cretaceous extinction of the dinosaurs (apart from birds, which were smaller, could eat diverse foods and fly) around 66 million years ago, is a more widely known global change. There is good evidence that a large asteroid crashing into modern-day Mexico was involved, triggering global wildfires, tsunamis, blocking out sunlight and killing off vegetation. But there was also prolonged volcanism leading up to this extinction, which is likely to have contributed through progressive global heating over many thousands of years.
The fact that climate has changed through natural processes in the past has been used by sceptics/deniers, including a sizeable proportion of geologists, to claim the current warming is simply the latest example of a natural change. However, the following analysis shows this simplistic interpretation is not correct because of the orders of magnitude shorter timeframe for the current warming event, which is clearly not linked to elevated levels of volcanism or extraterrestrial impact.
Studies of ice from drill cores in Antarctica and Greenland has proved important in explaining Recent climate trends. For example, CO2 concentrations have been measured in ancient air trapped in ice up to 500 thousand years old from the Vostok core, and these vary cyclically within the relatively restricted range of 180 to 290 parts per million (Figure 1). The last ice age ended around 12 thousand years ago, when CO2 levels were in the upper part of this range.
Temperatures were estimated from isotopic measurements of the ice. Figure 1 shows the general correlation between CO2 levels and temperatures, plus cyclic trends of several wavelengths – these so-called Milankovitch cycles reflect variations in solar irradiation related to the tilt and precession of the Earth’s axis and its elliptical orbit around the sun. In detail, temperature variations tend to acc change a little earlier, as expected if solar irradiation was a minor contributor to the temperature changes, which controlled the exchange of CO2 between the oceans and the atmosphere.
Figure 1 includes atmospheric CO2 measurements since the industrial revolution (at far right), which display a contrasting very rapid rise from around 280 to 425 parts per million, over a period of only about a century. This was accompanied by an increase in measured global average surface temperatures of almost 1.5°C, approaching the IPCC’s modelled level of concern. The only reasonable explanation for such a distinctive rapid increase in CO2 i is an enhanced greenhouse effect, resulting from addition of GHG to the atmosphere (and oceans) from burning fossil fuels, and this is supported by the distinctive isotopic compositions of atmospheric CO2. This means the current warming can only have a minor natural component, and sceptics/deniers disputing this are, unwittingly in some cases, acting unethically in opposing climate mitigation actions.
This analysis supports the IPCC’s conclusion that a sustainable future depends on drastic cuts to GHG emissions from human activities by mid-century.
3. WHAT DOES DECARBONISATION ENTAIL?
Global decarbonisation is a huge technological and economic transformation that will affect everyone. It requires substantial reductions in GHG emissions across all major sectors: electricity generation, transport, manufacturing, mining, construction, agriculture, and households. About 80% of all global energy use for these essential activities is currently provided by burning of fossil fuels, underscoring the magnitude of the task, but increasing rates of renewable and nuclear energy installation are encouraging.
The roles of governments involve maintaining and communicating long-term strategic plans, investing in research and development, supporting workforce transitions, and ensuring equitable outcomes for regions. The private sector will play central roles in exploring for and producing high-tech minerals, building renewable infrastructure, expanding power storage capacity, electrifying transport, implementing lower-emission industrial processes, scaling recycling systems, and manufacturing batteries and other renewable technologies. Households and individuals need to contribute, through consumer choices, energy use, and participation in distributed generation systems.
In Australia, the Labor government programs have prioritised renewable energy development and discovering and processing critical minerals. The latter are a diverse group of some 50 or so elements, which are essential for batteries, strong magnets, semiconductors, renewable power systems, and defence technologies, but have supply chains at risk. They include lithium, copper, cobalt, nickel, manganese, graphite, and the rare earth elements.
3.1 Sectoral considerations
Electricity generation is the largest source of Australia’s 1 light emissions. Transitioning to predominantly renewable energy requires:
transmission lines to connect renewable power generation sites to the grid;
upgrading the many ageing parts of the grid;
large-scale power storage systems (batteries and pumped hydro) to balance wind and solar variability;
land access for renewable generation and transmission corridors;
ensuring effective management of “new generation” power grids: there have been serious failures of renewable-heavy grids, notably the several-day blackout across the Iberian Peninsula in April 2025, and the major outage triggered by a storm in South Australia in 2016. Key issues are the intermittency of solar and wind power, their inability to resist changes and to black-start the system by themselves. There is a need for inertia from turbine-generated power, with sufficient dispatchable generation (e.g., hydro, gas, geothermal, and nuclear) to ensure grid stability.
Offsetting measures, or carbon capture and storage where feasible, will be needed to compensate for emissions from gas firming.
Nuclear micro-reactors, or small modular reactors (SMR), which are two or three orders of magnitude smaller than conventional reactors, are being actively pursued, particularly to power the AI revolution. In the US, Nano Nuclear Energy Inc. is seeking a permit to build a plant in Illinois in 2027, and in UK Rolls Royce SMR has major backing, including UK government funding and site plans at Wylfa, near Liverpool, and agreements and project selections in the Czech Republic and Sweden. While these modular reactors are developing rapidly, they still a few years from full commercialisation. They will be built in factories, shipped on trucks, and produce power at remote sites, for example, a data centre, or a mine, independent of the grid — all within months. They will run for years without refuelling, meet strict safety standards and have generally manageable water-cooling requirements.
Transport will increasingly rely on electrification and new generation fuels. Adequate infrastructure for charging and refuelling is essential. BMW and Toyota have collaborated in developing hydrogen fuel cell vehicles, and are currently working with Repsol and Bosch to commercialise a 100% synthetic fuel, Nova 95, made from agricultural and forestry residues, used cooking oils and other sustainable organic wastes; this produces over 70% less CO2 emissions than conventional petrol. Heavy freight, aviation, and shipping will all need technological improvements, including lighter large batteries and major efficiency gains. Rolls-Royce’s UltraFan program for aviation engines already promises a 25% increase in fuel economy using aviation fuel.
Manufacturing and construction must reduce emissions associated with production of major commodities like steel, concrete, and fertiliser, which are currently difficult to decarbonise. Green hydrogen is likely to play a leading role but must scale significantly using renewable power to become cost competitive.
Agriculture needs to reduce methane emissions from ruminants, adopt lower-emission fertilisers, switch to electric or other low/no GHG emissions farm equipment, and increase carbon sequestration in soils and vegetation.
Mining must transition from diesel to renewables, or other net zero GHG emission energy systems. It must continue to prioritise exploration and mining of critical minerals, phase-out of coal production, and reinforce its commitments to continuing improvement. Cleaner rare earth refining methods are an important research priority; until recently, most customers have been content to have China do this but, with current threats to supply and concerns about environmental impacts, it is important that Australia and other western nations develop and use cleaner processes. Increased exploration for natural hydrogen resources is also warranted.
It is important that all of this is done strategically and smartly to counter Australia’s high cost-structure, which will be difficult if there is continued strong opposition from influential but incompletely informed sceptics/deniers.
While current and projected technological advancements mean that fossil fuels can be phased out over time, production will need to continue in the near-term to help meet growing global power demand resulting from increasing population and development, particularly the exponential growth of power-hungry AI and crypto mining. However, there must be a greater focus on minimising emissions during both production and use, which will involve offsets and/or technologies aimed at preventing CO2 from reaching the atmosphere, such as carbon capture and storage in geologically favourable areas.
3.2 Costs of decarbonisation
Decarbonisation is frequently framed in terms of cost, which will undoubtedly be extremely high. But the greater question is cost relative to business as usual – worsening of infrastructure damage, agricultural losses, heat-related health impacts, forced migrations, and escalating disaster recovery expenditure would place increasingly higher burdens on current and future economies. There is no cheap way to minimise the risks of irreversible impacts on Earth systems, which threaten the future of humankind if not addressed.
When renewable-heavy grids are in place, power prices will benefit from not having the fuel costs of traditional power sources, and from the falling prices of components for renewable systems. These savings will be offset to some extent by measures needed to ensure electricity is provided continuously at constant voltage and frequency.
3.3 Benefits from decarbonisation
Decarbonisation will bring major universal benefits but, given inertia in the climate system, these will be progressive over several decades. In addition to minimising the risks of exceeding climate tipping points, it will deliver cleaner air and water, improved public and environmental health, new high-skill industry sectors, and regional economic diversification.
Comprehensive analyses by two highly qualified academics and government advisors, Professors Ross Garnaut and Alan Finkel, have shown how Australia can become a renewable energy superpower. They infer that Australia will be a major global supplier of critical minerals, for which demand is skyrocketing, and that renewable power and automation will underpin cost-effective and low-impact mining and value-adding of the nation’s mineral resources, including manufacture of high technology items, and green hydrogen production.
4. ARE THERE ENOUGH CRITICAL MINERALS?
The availability of the vast quantities of critical minerals has been cited as a constraint on the rate at which global decarbonisation can occur. However, whenever requirements for sourcing copious quantities of particular mineral commodities have arisen in the past, these have always been satisfied.
With increasing exploration and metal prices, new ores are found, lower grade resources became economic, recovery from secondary sources (for example, from mining wastes and recycling) increases, and substitute commodities are commercialised. That said, timing remains a concern, not least because it takes at least a decade from discovery of new deposits to commencement of production.
As Australia already has several world-class critical mineral mines, and many deposits that have not yet been comprehensively evaluated (Fig. 2), it is well placed to be a major contributor to, and beneficiary from, global decarbonisation.
The governments of Australia, the USA and Canada are funding collaborative efforts to support exploration for, and speeding up production from, new critical mineral deposits. Each of these countries has major potential for new discoveries, and Australia has the advantages of an extensive coverage of open-source geoscientific data, company reports on earlier exploration, and advanced research on exploration beneath cover.
It is impossible to ignore China’s dominance in supply and refining of critical minerals – the result of foresight and long-term strategic planning, which has proved much more difficult to achieve in Western democracies. Its rare earth reserves are greater than in any other country, it processes these minerals at considerably lower costs than elsewhere, and it has stakes in critical mineral operations around the world China’s mining and refining activities at home and in developing countries are far from best practice, and this will become a liability as demand for cleaner products increases, and additional supplies from other sources come on stream, unless they invest in more sustainable practices.
Further, reliance on China can be reduced by the West prioritising the development of cleaner rare earth processing technologies, and new chemistries for batteries and other high-tech applications based on non-critical materials (e.g. sodium for lithium in batteries). Australia has significant research and development programs aimed at adding value to its mineral resources, including manufacturing next generation batteries and other technologies for renewable grids, plus high-tech components such as strong heat-resistant magnets and specialist catalysts.
5. ARGUMENTS AGAINST THE NEED FOR CLIMATE ACTION
Because the publicity given to the pronouncements of prominent sceptics/deniers is causing uncertainties in the minds of many people, it is important to critically appraise their main claims for opposing climate action. These are summarised in bold below, along with my comments:
The current warming is a natural cycle, just like climate change events seen in the geological record, so we cannot stop it. This is the most cited, and readily accepted claim. However, as discussed above, this is ruled out because the current rate of global warming is orders of magnitude faster than for past examples of natural warming, and correlates with rapidly increasing atmospheric greenhouse gas (GHG) emissions since the industrial revolution.
The mediaeval warm period in North Atlantic countries, when there were vineyards in Britain, shows there has been very rapid historical natural warming. However, evidence of similar warming has not been found elsewhere in the world, implying this was a regional rather than a global event – regional climate variations are not uncommon.
Scientific research rarely gives absolute answers, so it is not proven that human activities are complicit in the current climate change event. However, the science must be taken seriously when multiple lines of evidence agree, and the IPCC has built a robust picture by studying the issues from different perspectives and considering criticisms received along the way.
Climate modelling cannot be trusted as it has provided a range of scenarios. The modelling is as good as the models used, the quality and quantity of input data, and the available computing power, all of which have improved greatly over the years. There is now a clear consensus that there are major risks if CO2 emissions are not drastically reduced.
The concentrations of CO2 in the atmosphere are so low that they could not cause global warming. This is simply not true — natural baseline levels are sufficient for growth of organisms and maintaining temperatures favourable for life.
Climate research and modelling are biased by opportunities for funding and “groupthink”. This is not consistent with the fact that many different organisations and individuals have been involved — not all research has been conducted by academics dependent on special research funding, and scientists typically seek to advance knowledge and their individual reputations, rather than associate with the thinking of other scientists.
Any overall benefits from decarbonisation will be more than offset by the costs. This ignores worsening of impacts and the risks of irreversible changes and collapse of natural systems. Decarbonisation costs will undoubtedly be extremely high, but business as usual would place increasingly higher burdens on current and future generations. The benefits of decarbonisation will be progressive over several decades, and include: a) minimising the risks of exceeding climate tipping points, cleaner air and water, and improved public and environmental health, and b) opportunities for new high-skill industry sectors, and regional economic diversification as Australia becomes a renewable energy superpower, and major global supplier and value-adder of critical minerals.
Renewable power is more expensive. When renewable-heavy grids are in place, power prices will benefit from not having the fuel costs of traditional power sources, and from the falling prices of components for renewable systems.
More than half of the petroleum produced is used for manufacturing materials such as plastics, carbon fibre, and fertilisers, so we will always need lots of it. Innovative research, led by the US, into use of waste biomass (for example, lignin from paper manufacture), and CO2 recovered from the atmosphere are showing early promise for replacing feedstock from petroleum, and membrane technologies are being developed to replace energy intensive fractional distillation for separating petroleum components. These will result in major decreases in GHG emissions when scaled up for commercial applications.
The amounts of critical minerals needed are so vast that global decarbonisation is an impossible dream. Critical minerals demand is increasing rapidly for decarbonisation, defence, AI, and other high-tech applications. While supplies are a major concern, there are reasons for optimism, including substitution, as discussed in the previous section.
Australia is such a minor emitter that it will make no difference if it does not decarbonise. We are in fact the fifth highest emitter of GHGs per head; decarbonising will provide benefits, while not acting will undermine our global credibility and future export competitiveness.
CO₂ is plant food, so more is good. While plants obviously do use it, increasing CO₂ is not universally beneficial to plants and, importantly it is building up rapidly in the atmosphere and temperatures are rising, with potential impacts on agriculture.
Most CO₂ is taken up by the oceans. True, but it is building up in the atmosphere, and the oceans are heating and acidifying, impacting on marine life, food sources, and marine infrastructure.
More CO₂ is coming from volcanism, particularly along mid-ocean ridges, than burning fossil fuels. However, the overall levels of Recent volcanic activity are not particularly high, and it has been estimated that fossil fuel use produces at least a hundred times more CO₂.
Solar variation is more important than GHG emissions. As discussed above, studies of CO2 levels and temperatures in air trapped in ice sheets show cyclic changes linked to solar variations, but these are much smaller than the changes since the industrial revolution, demonstrating solar effects only play minor roles in Recent climate change.
Decarbonisation will affect rural communities unfairly. Regions will continue to evolve, and some will have opportunities to benefit from renewable infrastructure, mining expansion, associated service industries, and new employment opportunities.
Disastrous weather events have always happened. The growing field of attribution science shows their frequency, intensity, and extent are linked to global warming; yesterday’s extremes are today’s normal.
There are always dire warnings about something or other, that never eventuate. Those based on sound evidence do usually happen.
The most polluting countries are not doing enough to achieve their Paris Agreement targets, so why should Australia bother. The reality is that China and India are putting a lot of effort into installing more renewable and nuclear power. China’s progress in cutting GHG emissions is particularly notable. Further, despite President Trump’s proclamation that climate change is a hoax, the US is making considerable progress in installing renewable technologies and increasing nuclear capacity.
Net zero will not be achieved by 2050. This is correct – China and India have announced they are aiming to reach this target by 2060, while Russia, Ukraine, Israel, and a number of African, Asian, and other nations have other priorities. This is not an argument against curtailing GHG emissions.
Therefore, the body of science supporting the IPCC’s conclusion that there is a need for urgent actions to mitigate the impacts of the current global warming event is not undermined by counterclaims of climate sceptics/deniers. This means there are major ethical issues in risking the future of humanity on the basis of unsubstantiated claims.
6. CONCLUDING REMARKS
This critical evaluation of publicly available information supports the IPCC conclusion that current global warming is predominantly caused by GHG building up in the atmosphere as a result of burning of fossil fuels.
It is extremely concerning that such a vital matter as maintaining Earth systems and securing a sustainable future for humanity has, to a significant degree, been hijacked by outspoken conservatives. There is no room for hubris, ideology, or self-interest – the risks of business as usual are far too great! Ignoring the scientific evidence and actively encouraging the transition to low carbon economies be stopped or slowed raises serious ethical issues. This is akin to promoting a flight on a plane that has a significant chance of crashing.
Despite conflicts, economic woes, and scepticism, it is vital that decarbonisation becomes an international priority if we are to progressively counter the impacts of warming, and minimise the huge and escalating costs for repair, mitigation, and adaptation.
Acknowledgment
Constructive comments were provided on an early draft of this article by Profs. Peter Cook and Tony Eggleton, and Dr Will Howard.
Picture credit: the image at the top was created using ChatGPT
Other articles in the IAPG Blog:
IAPG - International Association for Promoting Geoethics:
IUGS - Commission on Geoethics:
EGU - Geoethics Working Group: https://www.geoethics.org/egu-gwg
CIPSH - Chair on Geoethics:
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