It is a well-known fact that CO2 is contributing to global warming. But there are other greenhouse gases like methane that also influence climate change. The present speed at which the change is happening is disruptive. SHALINI SAKSENA speaks with climatologist PROFESSOR MURARI LAL who says that solution lies in newage technology
A study published by researchers at Duke University has thrown some alarming figures. It says that India has lost 259 billion hours of labour annually between 2001 and 2020 due to global warming. The loss of labour hours due to humid heat has cost India `46 lakh crore which is equivalent to almost seven per cent of the nation’s gross domestic product (GDP) in 2017, the study said.
Carbon dioxide, a by-product of fossil fuel combustion, is the principal greenhouse gas contributing to global warming. However, climate change is also influenced by greenhouse gases, including methane, nitrous oxide, and other industrial-process gases.
One is told that methane is 24 times more potent greenhouse gas than carbon dioxide with important implications for climate change. “Although methane has a much shorter atmospheric lifetime than carbon dioxide (CO2) — around 12 years, compared with centuries for CO2 — it absorbs much more energy while in the atmosphere. The methane gas (CH4) accounts for 18 per cent of greenhouse gases, is responsible for more than a quarter of global warming which comes majorly from landfills, agriculture, and the energy industry. Thus, while methane tends to receive less attention than CO2 until now, reducing methane emissions will be critical for avoiding the worst effects of climate change,” Professor Murari Lal, a climatologist says.
Besides the Glasgow Declaration and the parties’ individual Nationally-Determined Commitments (NDCs) to limit emissions in COP 26 (as agreed under the Paris Agreement), more than 100 countries signed a first-of-its-kind pledge to cut emissions of methane by 30 per cent by 2030, in combating climate change. The signatories represent 70 per cent of the global economy, including six of the world’s top 10 methane polluters. Reducing methane emissions from oil and gas operations is among the most cost-effective and impactful actions that governments can take to achieve global climate goals.
“The importance of this breakthrough in COP 26 can’t be overlooked and yet it sounds too good to be true. A major concern is that several methane polluting nations — including Turkmenistan and Russia — haven’t signed the pledge. Similarly, the commitment is voluntary and lacks enforcement mechanisms, as is the Paris Agreement. Therefore, its success will depend on countries holding themselves (and each other) accountable. Unfortunately, the world has a bad track record when it comes to this,” Lal opines
Unlike CO2, methane only lasts for 12 years in the atmosphere. Methane, that has a higher global warming potential, traps heat in the atmosphere 80 times more effectively than CO2; therefore even a tiny amount of it in the atmosphere can have huge effects on the climate. Reducing methane emissions in the atmosphere will pay off very quickly for the planet and for human health. Also, up to half of human-generated methane emissions can be cut at low or even negative cost using existing technology.
The world’s wetlands contribute about three-quarters (75 per cent) of the enduring natural sources of methane. Agriculture and livestock on the other hand is the largest anthropogenic source of methane emissions, accounting for around a quarter of the total, followed by the energy sector, which includes coal, oil, natural gas (most of it is methane), and biofuels. The oil and gas sector emitted around 70 metric tonne of methane (approximately 2.1 Gt CO2-eq) in 2020 — over five per cent of global energy-related greenhouse gas emissions.
“The present speed of warming of our planet is much faster than what we have experienced historically, and climate change at that speed is disruptive. It is not just a matter of getting warmer; traditional growing seasons and weather patterns will change, disrupting our established ways of life, including how we produce our food. It is in this context that perhaps reducing methane emissions is one of the most cost-effective strategies to rapidly reduce the rate of warming and contribute significantly to global efforts to limit temperature rise to 1.5° C. The UN has called for a 45 per cent reduction in methane emissions below a 2030 business-as-usual baseline, an aggressive cut that would avoid nearly 0.3° C of global warming by the 2040s, while improving human health and agricultural yields through reduced ground level ozone,” Lal says.
Wetlands remain a major area of concern with respect to climate change. Recent studies suggest that high rates of anaerobic (no oxygen) methane oxidation in freshwater wetlands can substantially reduce atmospheric emissions of methane. Methane, primarily from agriculture and livestock, contributes 16 per cent of all anthropogenic greenhouse gas emissions. Waste management, energy use (which includes coal, oil, natural gas and biofuel), and biomass burning also contribute to CH4 emissions.
Methane routinely leaks out from oil and gas wells, pipelines, and processing facilities into the atmosphere, exacerbating climate change. Methane is also emitted by natural sources like natural wetlands. Past estimates have suggested that about 2.5 per cent of human-induced climate warming can be attributed to rice farming.
“Rice production is estimated to be responsible for 10 per cent to 12 per cent of total methane global emissions, mainly due to its anaerobic decomposition during its production processes. The flooded rice fields in waterlogged soil is a perfect breeding ground for methanogens, the microbes that produce methane gas,” Lal tells you
Approximately 20 per cent of India’s anthropogenic methane emissions come from enteric fermentation, manure management, coal mines, municipal solid waste, natural gas, and oil systems. Wetland rice fields have been identified as one of the major sources of methane emission in India.
“Methane emission from wetland rice cultivation is expected to increase due to the likely intensification of rice cultivation in the coming decades. Alternate wetting and drying irrigation can effectively reduce CH4 emissions and total water use. Improved high yielding rice varieties together with efficient cultivation techniques will also significantly contribute to the curtailment of the methane emission fluxes,” Lal says.
China is responsible for the most emissions from agricultural production, followed by India, Brazil and the US during the past 20 years. Together, these top four agricultural emitters were responsible for 37 per cent of global agricultural production emissions. China and India’s agricultural production emissions have increased by 16 per cent and 14 per cent, respectively since 2000. However, in terms of per capita agricultural emissions, the top three countries are Australia, Argentina and Brazil.
“In order to keep warming to 1.5° C, the limit scientists assert is necessary for preventing some of the worst impacts of climate change, significant changes in technology, policies and farming practices would be necessary to reduce agricultural production emissions (mainly nitrous oxide from synthetic nitrogen fertilizer use and production, and carbon dioxide, both from energy used to produce fertilizer and other chemicals, and from generating electricity for farm use) by 40 per cent between 2016 and 2050 and increase carbon removal from the atmosphere with vast amounts of reforestation,” he explains.
He tells you that majority of agricultural production emissions come from raising livestock.
“Globally, more than 70 billion animals are raised annually for human consumption. The biggest single source is methane from cow burps and manure. Enteric fermentation (fermenting acetate and H2-CO2 in soils into methane and carbon dioxide) — a natural digestive process that occurs in ruminant animals such as cattle, sheep and goats — accounts for about 40 per cent of agricultural production emissions in the past 20 years (primarily methane, mostly from cattle digesting grass, and both methane and nitrous oxide from manure management),” he says.
In India, major contribution to methane emission by livestock during the past few decades has from buffalo, followed by cattle, swine, goat, sheep and other species. Buffalo shared about half (50.8 per cent) and cattle 39.6 per cent of the total manure methane emission.
Interestingly, only marginal changes in head count of these livestock have taken place in India during the past one and a half decade. Methane emissions in future from dairy and other categories of livestock populations could be reduced substantially through proper dairy herd management (and diet management — e.g., feeding garlic plants to live stocks) without compromising animal production.
The natural gas demand is expected to grow worldwide in the coming decades in contrasts to coal and oil, which would drop globally by almost 60 per cent and 30 per cent respectively by 2040. Fossil fuel operations currently generate nearly one-third of all methane emissions from human activity. Action on methane is therefore one of the most effective steps the energy sector can take to mitigate climate change.
Quantitatively, the energy sector is responsible for around 25 per cent to 30 per cent of the total anthropogenic methane emissions which includes emissions from coal, oil, natural gas and biofuels. In the oil and natural gas industry, methane is released during upstream production when natural gas is flared or vented. Methane is also released in small leaks, called fugitive emissions, from faulty valves and drilling equipment (unintentional releases) used in drilling and production.
One of the biggest hurdles to effective regulation of methane from the energy sector– including oil, natural gas, coal and bioenergy is the extent of uncertainty — about the magnitude of emissions, emissions sources and variability including lack of reliable data on leaks.
According to IEA estimates, the methane emissions from the oil and gas sector will need to fall to around 20 metric tonne per year by 2030 — a drop of more than 70 per cent from levels in 2020. It is recognised now that methane leaks are not an inevitable part of today’s oil and gas business. They can be reduced cost-effectively — and this has to happen if the world is to address climate change.
Considering average natural gas prices from 2017-2021, almost 45 per cent of current methane emissions from oil and gas operations could be avoided with measures that would have no net cost. Policy makers have at their disposal well-established policy tools that have already been demonstrated in multiple contexts to drive these emissions reductions, for instance Leak Detection and Repair (LDAR) requirements, staple technology standards and a ban on non-emergency flaring and venting.
Unfortunately, the methane releases and leaks in the oil and natural gas industry are often intermittent and easy to miss. In local areas, ground-based sensors can detect leaks, but they are not very effective.
Drone and airplane surveys are time-consuming and costly, and most of the world is inaccessible by air.
The solution lies in powerful new imaging technology. “A methane-hunting satellite can sniff out the emissions and track them to their sources. Various satellites with multiple sensors in operation today can provide estimates of the atmospheric concentration of methane across geographic areas,” Lal says.
For example, the satellite Sentinel 5P (Precursor), part of the European Space Agency (ESA) Copernicus programme, provides readings of methane concentration across areas of 5 km by 7.5 km, covering the whole world on average every four days. The satellite GHGSat covers a much smaller area each day but can provide data at a very fine spatial resolution (around 50 m by 50 m).
“The coverage and accuracy of these readings is only going to improve, especially with the envisaged launches of the Environmental Defense Fund’s MethaneSat, ESA’s Sentinel 5 and additional satellites from GHGSat. Targeting emitters on a global scale from space in the coming years would be an important new tool for routine sustained monitoring of greenhouse gases for developing regulations and guiding enforcement to combat climate change,” Lal tells you.
We have never been more in need of urgent action than now to combat climate change. There has been a shift in the scientific community’s awareness of the scale and speed of needed action. There is not much time left to avoid setting the world on a dangerous, potentially catastrophic trajectory.
“For the climate crisis to be resolved, the world must first reduce greenhouse gas emissions significantly and then achieve net-zero emissions by the middle of the century or earlier. Methane leaks from abandoned oil and gas wells must be prevented and coal mines must be cleaned up. The challenge presented by methane emissions from oil and gas in tackling the major leaks promptly would also require key oil companies to pursue and maintain high operational standards, and policy makers to put in place well-designed technical support and policy regulations. A smart national action plan would be needed that would require polluters to pay for their methane emissions — and offer oil and gas companies help in cleaning up their act. Since methane is a valuable product in the oil and gas industry and can often be sold if it is captured, this revenue can help offset some of the costs of deploying the measures needed to prevent the emissions and leaks,” Lal says.