Pearls and Irritations

Burning of all fossil fuels continues to increase. Gas is not better for the climate than coal but the myth continues and companies increase production. The fertile crescent is no longer fertile.

Fossil fuels still burn brightly

The bees in my bonnet began buzzing briskly when they saw the two graphs below.

Look at the graph on the right and one might take heart from observing the decreasing share of ‘primary energy’ consumption (that’s all energy, not just electricity generation) provided by oil since 2000 and coal since 2011. Also encouraging is the increasing share provided by renewables (wind and solar) throughout the century.

However, to understand what has been happening to greenhouse gas emissions the left-hand graph tells the fuller story. Here we can see that the total energy consumed globally increased 50% between 2000 and 2022 and that the amount of energy produced by fossil fuels increased from about 350 Exajoules in 2000 to about 500 in 2022. In fact, each one of coal, oil and gas increased the amount of energy they produced between 2000 and 2020. The consequence, of course, is that the amounts burnt and the greenhouse gases produced also both increased.

So, despite a 5% reduction in fossil fuels’ share of the total energy pie between 2000 and 2022, the amounts of fossil fuels burnt and greenhouse gases released into the atmosphere increased by over 40%. Not much justification for optimism about the end of the fossil fuel era there.

I keep droning on about it but it’s worth repeating: look at the absolute amounts of fuels used, not the percentages, if you want to know what’s really happening to energy generation and the climate.

No, gas is not better for the climate than coal

The gas industry is relentless in asserting that gas is better for the climate than coal. This is because when only end-use combustion is considered, gas emits half as much CO2 as coal. However, a new study that examined all uses of coal and gas and included measurement of the leakage of methane into the atmosphere has substantially added to the already compelling evidence that gas is not better for the climate than coal.

To simplify matters somewhat, the warming potential of coal and gas can be boiled down to the amount of three gases, CO2, methane (CH4) and sulphur dioxide (SO2), that each fuel produces during their whole life-cycle. This starts with the commissioning of facilities and the extraction process and proceeds through processing, transporting, burning and waste disposal to the decommissioning of facilities. This is represented in the diagram below, coal to the left, gas to the right.

CO2 and methane increase global warming by acting like a blanket around the Earth, while sulphur dioxide reduces warming by acting as a barrier to incoming solar energy.

One of the tricky elements in all this is that because methane’s warming effect is so much greater than CO2’s, the amount of methane that leaks into the atmosphere during the life-cycle of coal (mostly at the mine site) and gas (along the whole supply chain) is a crucial element in comparing the two overall. A further complication is the efficiency with which sulphur dioxide is ‘scrubbed’ from the emissions at coal burning power stations. The amount of sulphur dioxide produced during the life-cycle of gas is generally very small.

Putting all that together, the new study shows that a methane leakage rate of 5-8% during gas’s life-cycle puts gas on a par for global warming with coal, even accounting for the fugitive methane emissions from coal mines. With efficient sulphur dioxide scrubbing in place, the gas leakage rate for parity with coal can be even lower.

Measurement of methane leakage from coal and gas production lines has been increasing in both volume and accuracy in recent years. The leakage from gas production sites alone can be anywhere between 0.1% and 66%.

It does not make sense to switch from coal to gas; gas is not a rational transition fuel. It’s not just coal we need to get rid of. We need to end the whole fossil fuel era as quickly as possible if we are to avoid the worst consequences of global warming. But for the short-term, while we are still producing and burning gas, it is essential that companies responsible for gas production, and transportation (both by ships and pipelines) are forced to eliminate methane leakage and venting.

Regrettably, despite the Australian government signing the Global Methane Pledge to cut our methane emissions by 30% by 2030, our gas industry continues to emit, and under-report, vast quantities of methane via leaks and intentional venting.

Oil and gas company investments in the energy transition stall, but does it matter?

The five biggest oil and gas companies are reneging on previous commitments to cut fossil fuel production. Also, despite making immense profits last year (US$200 billion), they are making only half-hearted efforts to increase their investments in renewable energy. But, according to Bloomberg Green (you have to register to read the full article), this isn’t particularly significant in terms of the overall investment in the global energy transition.

From 2015 to 2022, the big oil and gas companies (not just the biggest five) increased their investment in low-carbon assets and technologies from about US$5 to US$35 billion per year. This represents an increase from 0.5% to 8.5% of the companies’ total capital expenditure being directed to low carbon systems.

However, while the oil and gas companies’ seven-year total of investment in the energy transition (US$113 billion) sounds a lot, it was less than 2.5% of the world’s total investment in the transition (US$4.8 trillion), and since 2018 the percentage has remained steady in the 2.5-3.0% range. These trends are clear in the graph below.

The point is that the oil and gas companies’ investment in renewable energy to date has not had much of an influence on the overall direction and speed of the transition. So how they fiddle around the edges of their investments is largely irrelevant – well, irrelevant to the transition that is, not to understanding their motivations and priorities.

A climate warning from the cradle of civilisation

… is the title of a story in the New York Times about how the area in Iraq between the Euphrates and Tigris rivers has changed in less than a century from being lush, fertile, verdant and thriving to an increasingly depopulated desert. It’s a long story so I’ve extracted a few of the photographs from it to provide an overview.

First, a reminder of where we are talking about and an indication of part of the problem: dams built on the major rivers and their tributaries both within Iraq and in neighbouring Turkey and Iran.

One outcome has been a 30% decrease over 80 years in the flow of the Tigris, while the population has almost quadrupled from 11.6 million to 44 million in the last 40 years.

The environmental and social consequences are immense and include shrinking wetlands, dry fields, dying livestock, abandoned farms, collapse of rural communities, and large-scale migration to growing cities which are already struggling to cope.

Still, that’s what happens when you don’t take good care of your rivers. Thank goodness we know better.

Oceans absorb nearly all the sun’s energy

We know that the oceans are getting warming, albeit more slowly than the land, and we know that this can be catastrophic for the Great Barrier Reef and other coral reef systems when there is an extended period of high water temperature over a reef.

Compared with land, water can absorb much larger amounts of energy with only a slight increase in temperature. Consequently, the oceans have been doing us all an enormous favour over the last 60 years by storing the vast majority (about 90%) of the additional solar energy that has been retained by the Earth because of the build-up of greenhouse gases in the atmosphere. This is very clearly demonstrated in the graph below.

Coral bleaching is not the only harmful outcome, however. Sea level rise, stronger cyclones, changes to the availability of marine food (for wildlife and humans), loss of habitat, accelerated melting of polar glaciers and sea ice, and changes to the circulation patterns of the oceans also result from warmer water.