The Arctic is warming faster than the rest of the globe and the effects are global. Bacteria responsible for escalating methane emissions. The false binary of system change or individual behaviour change.

Arctic warming

The temperature across the Arctic (north of 60^oN) in 2024 was 1.2^oC above the 1991-2020 average, making 2024 the Arctic’s second warmest year since records began in 1900. The consequences for various aspects of the weather (e.g., rainfall, snowfall, further global warming), the physical environment (e.g., Greenland ice sheet, sea ice, snow cover, sea surface temperature, tundra, boreal forests), land and marine animal and plant life, and Indigenous communities are reviewed in NOAA’s Arctic Report Card for 2024. The 4-minute video in the link provides a nice summary but I’ll highlight two issues, temperature changes and the Arctic’s net carbon balance. It’s important to note that although there are clear trends over time in these two dimensions, the changes are not uniform across the Arctic.

The land areas of the Arctic have been a net carbon ‘sink’ for thousands of years, with plants absorbing CO2 from the atmosphere and the soil and permafrost providing long term storage. Global warming is causing permafrost to thaw and release the long-stored CO2 and methane into the atmosphere. Wildfires have also been increasing in both intensity and hectares burnt and these have added massive pulses of CO2 to the atmosphere.

The map below displays temperature changes across the Arctic in 2024 compared with the average for 1991-2020. Areas that were warmer than average are orange and red, and colder than average areas are increasingly blue. Clearly, the warmer areas predominate in both area and intensity.

The graph beneath the map shows annual Arctic (red) and global (black) temperatures for 1900-2024 compared with the average for 1991-2020. Both have been on a steady increase since about 1970 but it’s clear that the temperature increase in the Arctic since 1900 has been greater (about 3^oC compared with about 1.5^oC) and that the rate of increase over the last 50 years has been quicker (almost triple the global rate – ‘Arctic amplification’).

The next map shows the Arctic’s net carbon balance over the last two decades. Purple areas have been sources of CO2 into the atmosphere. The darkest purple areas are responsible for the largest releases of CO2, due to wildfires. Green areas were carbon sinks. Overall, the Arctic was carbon neutral from 2001-2020 and while the boreal forests remain a carbon sink, the tundra has transitioned from a sink to a source. In the most recent years, the Arctic has become a net carbon source.

Rethink of what’s causing methane emissions to increase

Methane (CH4) is the second most important greenhouse gas (GHG), contributing a third of current global warming because over decades rather than centuries it has a much greater warming effect, ton for ton, than CO2. Because the climate crisis is here and now, not a hundred years away, current CH4 emissions are very important and the (relatively) good news is that there is the potential to significantly reduce the CH4 emissions arising from fossil fuel production over a decade or two. But fossil fuels are not the only source of CH4. Agriculture and waste are also significant sources and about 40% of the CH4 in the atmosphere originates from the natural environment.

The bad news is that the concentration of CH4 in the atmosphere has been increasing in recent decades apart from a pause around 1998-2008.

What has been causing this increase? The dominant view has been the production and burning of fossil fuels but this has been challenged by a study of the carbon isotopes in the CH4 released into the atmosphere. This has shown that methane-excreting microbes on farms, in waste dumps and in wet environments are to blame. Wetlands includes both natural environments (e.g. swamps, peatbogs, tropical and freshwater wetlands and Arctic permafrost) and man-made environments (e.g. reservoirs, landfills and rice paddies).

This doesn’t entirely exonerate human activity, however, as methane production by the microbes increases as the temperature increases and also when there is more rainfall. This, of course, leads to a dangerous reinforcing feedback loop: more global warming leads to more CH4 production by wetland microbes which leads to more global warming and round we go.

But there isn’t just one universal type of microbial methane so the next step is to determine which particular wetlands are causing the soaring levels of CH4 so that action can be taken to try to control them. Eliminating all human-induced methane emissions over the next 20 years could lower the temperature increase by 0.5^oC.

System change or individual behaviour change?

Regular readers will know that when it comes to tackling the big problems facing society – climate change, loss of biodiversity, poverty, international conflict – I very much favour system change. That’s not to say that individuals shouldn’t do things that are good for society or the environment or world peace but it is important for well-meaning individuals to realise that their personal behaviours, even if replicated by millions, are highly unlikely to change the world.

Hannah Ritchie, Deputy Editor and Lead Researcher at the excellent Our World in Data, takes a similar view, seeing the polarising debate about who is responsible for climate change and who should fix it as being a ‘false binary. It’s not one or the other. It’s both’. Institutions need to make it affordable and easy for people to change their behaviours (eat less meat, drive an EV, use public transport, install rooftop solar, etc.) and people need to show institutions the direction they want things to go. Working together can create a virtuous or reinforcing cycle:

Ritchie recognises that individual behaviour change is hard. You don’t need to tell me that, I worked in health promotion and public health for 40 years. But whole populations not just individuals do change their behaviours and I can think of many examples that have affected, for good and bad, people’s health in recent decades – reduced smoking rates, routine buckling up of seat belts, regular ‘slip, slop, slapping’, high popularity of calorie-rich fast-food, use of social media, for example. Ritchie sums it up very nicely: ‘you need to give people what they want, and you need to make it affordable and easy’, and then her killer point: ‘“What they want”, to be clear, is not a petrol car or a gas boiler. It’s a convenient and comfortable way to travel from A to B and a warm home’.

Ritchie warns against being distracted by the myth that ‘every little helps’. We must do a lot to achieve big changes in demand and supply. She suggests some actions we can all take to reduce our personal carbon footprint, which you all know already, and finishes with four ways to make our ‘carbon handprint’ bigger than our footprint:

• Vote for candidates with positive climate policies.
• Signal to the market that you want low carbon products – vote with your wallet.
• Choose a career that contributes to solving these problems.
• Donate money to effective causes, especially those that don’t just tackle climate change and land use but also alleviate human suffering.

National research priorities

In August 2024, the Department of Industry, Science and Resources released Australia’s National Science Statement which opens by stating that ‘Through science and innovation, Australia will develop new industries that drive a dynamic economy, provide well paid jobs, improve our quality of life, preserve our unique environment and build a future made in Australia’.

The Statement is supported by Australia’s National Science and Research Priorities, of which there are five:

• transitioning to a net zero future
• supporting healthy and thriving communities
• elevating Aboriginal and Torres Strait Islanders knowledge systems
• protecting and restoring Australia’s environment
• building a secure and resilient nation.

I was somewhat sniffy last week in my comments about our Prime Minister’s lack of policy ambition but, credit where it’s due, it’s difficult to imagine that a Coalition government’s five research priorities would include two about the environment and one each about healthy communities and Indigenous knowledge systems.

What’s a pingo?

I know it sounds like one of Bertie Wooster’s dopey aristocratic friends but no, that’s not correct.

A pingo is a hill with an ice core that is found in regions of permafrost in the Arctic and subarctic. They can be up to 70 metres high and a kilometre in diameter. There are estimated to be about 11,000 pingos. The word pingo means conical hill in the Inuvialuktun languages.

Pingo in the Mackenzie River Delta, Canada. Photo by Renaud Philippe.

Pingo in the Mackenzie River Delta showing the ice core.

Seasonal greetings to everyone regardless of your religious affiliations, and best wishes for the year ahead. My next contribution to P&I will appear on January 26^th.