Wednesday, September 01, 2021

Climate change challenges of the 21st century

The Moon and Earth's Troposphere: Silver-blue noctilucent clouds are shown extending far above the orange-coloured troposphere, the lowest and densest part of Earth's atmosphere. Photo: by NASA taken by the Expedition 28 crew (began May 2011) aboard the International Space Station.

July 2021 was Earth’s hottest July since global record-keeping began in 1880. July had two $25bn flood disasters and the Earth’s hottest "reliably measured temperature on record" was 54.4°C (130°F) at Death Valley, California." July 2021 was the sixth wettest July on record in the US.

Lytton, West Canada, had a temperature of 49.6°C on June 29 (a record beaten 3 consecutive days); Morocco: 49.6°C at Sidi Slimane, July 10 and the United Arab Emirates: 51.8°C at Swiehan, June 6.

Temperatures for Verkhoyansk, a remote Siberian town inside the Arctic Circle, hit 38°C on June 20, about 18°C above the average maximum daily temperature in June.

Fires ravaged forests in many parts of the globe.

Among EU27 countries Ireland had the highest per capita greenhouse gas emissions in 2019 at 12.8 tons of CO₂ equivalent which includes the main greenhouse gases. The EU27 was at 8.4; Germany at 10.1; Denmark 8.1; Sweden 5.2 and non-member the UK at 7.3. See chart. Luxembourg data are not reliable as over 40% of its workforce live in neighbouring countries.

The category is 'Total emissions and international aviation.' See the European Environmental Agency chart below. *Also check the detail of the dataset at end of the page.

Greenhouse gases make the Earth habitable but concentrations have risen 50% after a period of 800,000 years

While carbon dioxide (CO₂) only accounts for 0.041% of the Earth's atmosphere it can remain there for between 300 to 1,000 years according to the US National Aeronautics and Space Administration (NASA). However, the US Environmental Protection Agency (EPA) says "Carbon dioxide’s lifetime cannot be represented with a single value because the gas is not destroyed over time, but instead moves among different parts of the ocean-atmosphere – land system. Some of the excess carbon dioxide is absorbed quickly (for example, by the ocean surface), but some will remain in the atmosphere for thousands of years, due in part to the very slow process by which carbon is transferred to ocean sediments."

CO₂ is the primary greenhouse gas emitted through human activities and in 2019 it accounted for about 80% of all US greenhouse gas emissions from human activities. CO₂ from burning for example fossil fuels accounted for 62.4% of all greenhouse gas emissions in Ireland in 2019; Methane (CH₄) accounted for 24.6%; Nitrous Oxide (N₂O) 11.5% and the combined emissions of HFCs, PFCs, SF₆ and NF₃ accounted for 1.5% of total GHG emissions in 2019 (the latter are mainly attributed to refrigeration and air conditioning emissions.)

CH₄ and N₂O are mainly agriculture-related in Ireland and accounted for 36.1% of GHG emissions.

Despite the pandemic, the world emitted more than 33bn tons of carbon dioxide last year (the International Energy Agency estimated the energy-related total as 31.5 GT - gigatons - while the EU's EDGAR - Emissions Database for Global Atmospheric Research estimated the energy-related total CO₂ at 38.0 GT in 2019).

EU27+UK total fossil CO₂ emissions have fallen over the past two decades and in 2019 were 25.1% lower than in 1990 and 22.2% lower than in 2005.

Atmospheric carbon dioxide measured by the US National Oceanic and Atmospheric Administration's (NOAA) peaked for 2021 in May at a monthly average of 419 parts per million (ppm). The level first topped 400 parts per million in 2014 and the May 2021 average was almost 50% higher than the preindustrial mean of 280 (bubbles of ancient air trapped in ice show that before about 1750, the concentration of CO₂ in the atmosphere was about 280 parts per million.). This extended back to about 800,000 years while periods of frigid ice ages in North America and Eurasia had CO₂ levels of around 180 ppm.

In 2019 Princeton University announced that "Gas bubbles trapped in... cores — which are the oldest yet recovered — contain pristine samples of carbon dioxide, methane and other gases that serve as 'snapshots' of prehistoric atmospheric conditions and temperatures, the researchers... reported in the journal Nature. The cores were collected in the remote Allan Hills of Antarctica."

Methane and nitrous oxide and other anthropogenic (resulting from human activities) concentrations in the atmosphere have also hit records over the last 250 years.

Data source: Reconstruction from ice cores, Credit: NOAA

The Earth’s atmosphere comprises about 78% nitrogen, 21% oxygen, 0.9% argon, and 0.1% other gases. The main greenhouse gases (GHG) are water vapour; carbon dioxide; methane; ozone; nitrous oxide and chlorofluorocarbons.

National Geographic says that the Earth’s atmosphere stretches from the surface of the planet up to as far as 10,000 kilometres (6,214 miles). Not all scientists agree where the actual upper boundary of the atmosphere is, but they can agree that the bulk of the atmosphere is located close to Earth’s surface. The atmosphere is divided into five different layers, based on temperature.

The layer closest to Earth’s surface is the troposphere, reaching from about seven and 15 kilometres (five to 10 miles) from the surface. The troposphere is thickest at the equator, and much thinner at the North and South Poles. The majority of the mass of the entire atmosphere is contained in the troposphere — between approximately 75 and 80%.

The GHGs absorb and re-emit infrared energy from the atmosphere down to the Earth’s surface and the greenhouse effect results in a mean surface temperature that is 33°C greater than it would be in its absence.

Without the greenhouse gases trapping heat, Earth’s average temperature would be -18°C, not +15°C (+59°F) and planet Earth would be inhabitable.

Even though carbon dioxide causes about 20% of Earth's greenhouse effect, while water vapour accounts for about 50%; clouds 25% and the rest is caused by small particles (aerosols) and minor greenhouse gases like methane, changes in carbon dioxide have driven past temperature changes.

In contrast, water vapour levels in the atmosphere respond to temperature.

"Already in 1990, we knew about humanity's impact on climate change, and yet we've emitted more than half of all emissions since 1751 in the last 30 years alone. If we had taken action then, today's young people and future generations would face a much easier challenge. We cannot afford another decade of inaction and have to flatten the emissions curve as part of Europe’s recovery from the COVID-19 pandemic" — Thorfinn Stainforth, Policy Analyst in IEEP's (Institute for European Environmental Policy) Low-carbon and Circular Economy Programme 2020.

Climate change science dates from the early 19th century

Baron Joseph Fourier (1768-1830) was a French mathematician and he went to Egypt with Napoleon Bonaparte in 1798. His 3 years in the North African country triggered a lifelong obsession with heat and its healing powers. His 'Théorie analytique de la chaleur' (1822; The Analytical Theory of Heat) showed how the conduction of heat in solid bodies may be analysed in terms of infinite mathematical series now called by his name, the Fourier series.

Fourier calculated that the Earth would be much colder if the incoming radiation from the Sun was the only warming effect. This in effect was a recognition of the greenhouse effect.

Claude Servais Mathias Pouillet (1791-1868), professor of physics at the Sorbonne and member of the French Academy of Science, invented the pyrheliometer, an instrument that measured the quantity of heat received by the Sun.

In 1856 Eunice Newton Foote ((1819-1898), an American amateur scientist and activist for women's rights, produced a scientific paper setting out how using glass cylinders, each encasing a mercury thermometer, resulted in the finding that the heating effect of the Sun was greater in moist air (water vapour) than dry air and that it was highest of all in a cylinder containing carbonic acid gas (carbon dioxide). She was the first scientist known to have experimented on the warming effect of sunlight on different gases and she went on to theorize that changing the proportion of carbon dioxide in the atmosphere would change its temperature. Foote's paper 'Circumstances affecting the heat of the Sun's rays' was read by a male member at the American Association for the Advancement of Science conference in 1856.

In January 1859, Irish-born John Tyndall (1820-1893) working in England, began studying the radiative properties of various gases. Part of his experimentation included the construction of the first ratio spectrophotometer, which he used to measure the absorptive powers of gases such as water vapour, "carbonic acid" (now known as carbon dioxide), ozone, and hydrocarbons. Among his most important discoveries were the vast differences in the abilities of "perfectly colourless and invisible gases and vapours" to absorb and transmit radiant heat.

Sir Ronald Jackson of the British Royal Institution (founded 1799) writes that "Foote had the insight to suggest, three years before Tyndall, that changing amounts of carbon dioxide and water vapour in the atmosphere could change the climate." While the ‘greenhouse effect’ "is responsible for the fact that our planet is warmer than it would be without an atmosphere. It makes the Earth habitable for life. Its operation is simple in principle. Heat, originally from the Sun, is radiated from the surface of the earth and absorbed by gases such as carbon dioxide and water vapour. Those, in turn, radiate heat themselves. That results in an increase in the average temperature of the surface and the atmosphere above what it would otherwise be.

What Tyndall had demonstrated unambiguously, and indeed for the first time, was the absorption and radiation by certain gases of what we now call long-wave infrared radiation."

In 1896, Swedish scientist Svante Arrhenius (1859-1927) was the first to link a rise in carbon dioxide gas, to burning fossil fuels with a warming effect. He suggested a doubling of the CO₂ concentration would lead to a 5°C temperature rise. Arrhenius won the Nobel Prize in Chemistry in 1903.

Nils Gustaf Ekholm (1848-1923), a Swedish meteorologist, in 1899 argued that then present rates of the burning of coal eventually could double the concentration of atmospheric CO₂.

Ekholm had this English language translation of a paper 'On the Variations of the Climate of the Geological and Historical Past and Their Causes' published in the January 1901 Quarterly Journal of the Royal Meteorological Society, London.

It was first published in Stockholm in 1899 as 'Om klimatets ändringar i geologisk och historisk tid samt deras orsaker' [On Changes of Climate in Geologic and Historic Time and their Causes].

Ekholm is said to have been the first person to use the term "green-house" in scientific writings in respect of CO₂.

"The atmosphere plays a very important part of a double character as to the temperature at the earth’s surface, of which the one was first pointed out by Fourier, the other by Tyndall. Firstly, the atmosphere may act like the glass of a green-house, letting through the light rays of the Sun relatively easily, and absorbing a great part of the dark rays emitted from the ground, and it thereby may raise the mean temperature of the earth’s surface. Secondly, the atmosphere acts as a heat store placed between the relatively warm ground and the cold space, and thereby lessens in a high degree the annual, diurnal, and local variations of the temperature."

The challenge of the century

The climate havoc in the Northern Hemisphere in this summer of 2021 has extended from Europe to China and North America. Last year the global pandemic resulted in the largest falls in both energy demand and carbon emissions since World War II. According to BP, the British oil firm, "the fall of over 2 GT (a Gigaton is equal to 1bn metric ton) of CO₂ means that carbon emissions in 2020 were back to levels last seen in 2011. However, in its annual 'Statistical Review of World Energy 2021' BP says "if carbon emissions declined at the same average rate as last year for the next 30 years, global carbon emissions would decline by around 85% by 2050... that is roughly mid-way between the rapid and net-zero scenarios, which are broadly consistent with maintaining global temperature rises well below 2˚C and below 1.5˚C respectively."

The huge challenge is to cut emissions without causing massive disruption and damage to everyday lives and livelihoods.

The latest United Nations' Intergovernmental Panel on Climate Change (IPCC) report, released in early August 2021, extends to almost 4,000 pages with 234 authors and some 14,000 citations to existing scientific studies. Twenty-six years after the first IPCC report, the scientists were able to detail a great deal of evidence of the scope of human-induced climate change and expectations of what the future might hold if greenhouse gas emissions continue to climb.

"It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred... Observed increases in well-mixed greenhouse gas (GHG) concentrations since around 1750 are unequivocally caused by human activities... Each of the last four decades has been successively warmer than any decade that preceded it since 1850. Global surface temperature in the first two decades of the 21st century (2001-2020) was 0.99 [0.84-1.10] °C higher than 1850-1900. Global surface temperature was 1.09 [0.95 to 1.20] °C higher in 2011–2020 than 1850–1900, with larger increases over land (1.59 [1.34 to 1.83] °C) than over the ocean (0.88 [0.68 to 1.01] °C)."

While the industrial era – and associated greenhouse gas emissions – began in the mid-1700s, reliable climate data dates from the mid-19th century. The period of 1850-1900 is used to approximate pre-industrial conditions. The IPCC estimates a likely temperature change of between -0.1 to +0.3℃ for the period 1750-1850.

Earth’s average temperature in the last decade was 1.09℃ warmer than the pre-industrial baseline. The IPCC says that in the northern hemisphere, 1983–2012 was likely the warmest 30-year period of the last 1,400 years (medium confidence).

In 2015 in Paris countries agreed to limit warming to a global average of 1.5℃. However, the IPCC now says that the Earth is likely to reach the crucial 1.5℃ warming limit in the early 2030s.

The report says global warming of 1.5℃, and then 2℃ will be exceeded this century unless we make deep cuts to CO₂ and other greenhouse gas emissions in coming decades.

The scientists warn that if current emissions' pledges are realised, they would amount to just a 1% reduction in global emissions by 2030, compared to 2010 levels. They say the number needs to be closer to a 50% reduction.

The IPCC says that many of the changes observed in the climate are unprecedented in thousands, if not hundreds of thousands of years, and some of the changes already set in motion — such as continued sea-level rise — are irreversible over hundreds to thousands of years.

Scientists say that unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions (GHG), limiting warming to close to 1.5°C or even 2°C will be beyond reach.

For 1.5°C of global warming (this is a global average and in parts of the world the swings in temperature will be a lot wider), there will be increasing heat waves, longer warm seasons and shorter cold seasons. At 2°C of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health, the report shows. "Climate change is bringing multiple different changes in different regions – which will all increase with further warming. These include changes to wetness and dryness, to winds, snow and ice, coastal areas and oceans."

Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and northern hemisphere spring snow cover have continued to decrease in extent (high confidence).

The rate of sea-level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence). Over the period 1901–2010, the global mean sea level rose by 0.19m [0.17m to 0.21m].

The atmospheric concentrations of carbon dioxide (CO₂), methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years. CO₂ concentrations have increased by 50% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land-use change emissions. The ocean has absorbed about 30% of the emitted anthropogenic (human activity) CO₂, causing ocean acidification.

Tropical forests losing the ability to absorb carbon

A Swiss pastor, Jean Senebier (1742-1809), is the first known person to suggest that plants suck CO₂ from the air. He grew plants under different experimental conditions and suggested that plants decompose  CO₂ from the air and incorporate carbon. This was later corroborated by discoveries about the mechanisms of photosynthesis.

The journal Nature published research in March 2020 on the role of forests as carbon sinks.

Tropical forests account for one-half of Earth’s carbon stored in terrestrial vegetation.

Globally, the terrestrial carbon sink is claimed to be increasing. Between 1990 and 2017 the land surface sequestered about 30% of all anthropogenic (human activity related) carbon dioxide emissions. Rising CO₂ concentrations are thought to have boosted photosynthesis more than rising air temperatures have enhanced respiration, resulting in an increasing global terrestrial carbon sink.

However, using ground, airborne, and satellite data, a group of climate scientists in 2020/2021 – including NASA scientists – created a new method to assess how the changes in forests over the past two decades have impacted carbon concentrations in the atmosphere.

More than half of the world’s forests are found in only 5 countries (the Russian Federation, Brazil, Canada, the United States and China) and two-thirds of forests are found in 10 countries. Since 2010, 129m trees are estimated to have died in California’s national forests, as a result of a hotter climate, insects, fire, and other factors, and between 2015 and 2020, the rate of deforestation was estimated at 10m hectares per year, down from 16m hectares per year in the 1990s. The area of primary forest worldwide has decreased by over 80m hectares since 1990 according to the UN's Food and Agriculture Organisation.

Researchers assessed trends in the carbon sink using 244 structurally intact African tropical forests spanning 11 countries, comparing them with 321 published plots from Amazonia and investigate the underlying drivers of the trends. The carbon sink in live aboveground biomass was in intact in African tropical forests, has been stable for the three decades to 2015 in contrast to the long-term decline in Amazonian forests.

The researchers noted "Despite the past stability of the African carbon sink, our most intensively monitored plots suggest a post-2010 increase in carbon losses, delayed compared to Amazonia, indicating asynchronous carbon sink saturation on the two continents... Overall, the uptake of carbon into Earth’s intact tropical forests peaked in the 1990s. Given that the global terrestrial carbon sink is increasing in size, independent observations indicating greater recent carbon uptake into the Northern Hemisphere landmass reinforce our conclusion that the intact tropical forest carbon sink has already peaked. This saturation and ongoing decline of the tropical forest carbon sink has consequences for policies intended to stabilise Earth’s climate."

A study led by scientists at NASA’s Jet Propulsion Laboratory (JPL) in Southern California and published in July 2021 identified whether vegetated areas like forests and savannas in 169 countries were carbon sources or sinks every year from 2000 to 2019.

In the period of 20 years, the research found that living woody plants were responsible for more than 80% of the sources and sinks on land, with soil, leaf litter, and decaying organic matter making up the rest. But they also saw that vegetation retained a far smaller fraction of the carbon than the scientists originally thought.

In addition, the researchers found that the total amount of carbon emitted and absorbed in the tropics was four times larger than in temperate regions and boreal areas (the northernmost forests) combined, but that the ability of tropical forests to absorb massive amounts of carbon has waned in recent years. The decline in this ability is because of large-scale deforestation, habitat degradation, and climate change effects, like more frequent droughts and fires. In fact, the study, published in Science Advances, showed that 90% of the carbon that forests around the world absorb from the atmosphere is offset by the amount of carbon released by such disturbances as deforestation and droughts

According to the researchers, forests collectively absorbed around 15.6bn metric tons (gigatons) of carbon dioxide from Earth’s atmosphere each year between 2001 and 2019, while deforestation, fires, and other disturbances released an average of 8.1 billion metric tons of carbon dioxide per year.

Forests around the world are estimated to absorb about a net 7.6bn metric tons compared with total global carbon emissions of about 36 gigatons in 2019.

The scientists created maps of carbon sources and sinks from land-use changes like deforestation, habitat degradation, and forest planting, as well as forest growth. They did so by analysing data on global vegetation collected from space using instruments such as NASA’s Geoscience Laser Altimeter System.

“A lot of research that has come before hasn’t been spatially explicit – we haven’t had a map of where carbon fluxes were occurring,” said Nancy Harris, research director of the forest program at the World Resources Institute in Washington and one of the study authors.

“The Amazon was considered a substantial carbon sink because of large tracts of pristine forest that soak up carbon dioxide,” said Sassan Saatchi, principal scientist at JPL and the study lead investigator. “However, our results show that overall, the Amazon Basin is becoming almost neutral in terms of carbon balance because deforestation, degradation, and the impacts of warming, frequent droughts, and fires over the past two decades release carbon dioxide to the atmosphere.”

“Many previous studies found that vegetation around the world absorbs a lot of atmospheric carbon dioxide,” said study lead author Alan Xu, a carbon researcher at JPL and UCLA (University of California Los Angeles). “It gives the impression that global forests are growing and getting bigger everywhere, but that’s not the case.”

It’s important to understand how regions around the world absorb and emit carbon dioxide, said Harris. “If we’re not getting these patterns right, we may be missing some of these ecosystems and how they’re affecting the carbon cycle.” But she is encouraged by the sheer amount of data becoming available to climate scientists on how the greenhouse gas moves between the atmosphere and Earth’s forests, grasslands, and other vegetated areas.

Saatchi is hopeful that having a more systematic and consistent approach to keeping track of which parts of the world are acting as carbon sources or sinks will enable better monitoring across regions and countries. “It could allow countries around the world to use the data as guidance for meeting their national commitments to the Paris Climate Agreement.”

"Forests absorb twice as much carbon as they emit each year," says Prof Martin Herold of Wageningen University & Research, the Netherlands. “But it also means that we cannot miss those sinks in global climate control.” In 2019 alone, the world lost 11.9m hectares of tree cover: “Healthy forests, soils and oceans help keeping carbon sinks in function. We cannot afford to lose the CO₂ absorption capacity of forests,” he says.

Annual average precipitation, in inches

In the last 30 years, compared to the 20th century

Planting trees?

In an August 31, 2021 article on carbon offsets in The Financial Times the authors ask "Can planting trees in Guizhou province cancel out emissions from natural gas burned for energy in offices and homes across China? That is the idea behind a deal struck in July by oil major Shell to supply PetroChina with an undisclosed quantity of liquefied natural gas branded 'carbon neutral.'

The deal was part of a nascent but growing trend, in which fossil fuel shipments are paired with carbon offsets — units that organisations can buy to compensate for their emissions and help their carbon-intensive cargoes appear greener."

“This is the latest attempt to try to market fossil fuels of any type as part of the transition [to clean energy],” says Gilles Dufrasne, of the not-for-profit group Carbon Market Watch. “I don't think there is such a thing as a ‘carbon neutral’ fossil fuel, it’s a bit of an oxymoron.”

The Science Based Targets, a corporate initiative, says offsets from counting toward corporate net-zero targets are not valid as firms must achieve the net-zero target by cutting emissions: "Understanding that reaching net-zero emissions globally requires all sources of emissions to be eliminated or neutralised with an equivalent amount of negative emissions, this strategy [offsetting] is not consistent with reaching a state that is consistent with reaching net-zero emissions at the planetary level."

While the chart above from the McKinsey management consultancy shows NG (Natural Gas) and LNG (Liquefied Natural Gas) in a more positive position than Fuel Oil and Coal, Gavin Thompson, vice chairman, Energy – Asia Pacific of Wood Mackenzie ─ a leading energy consultancy says:

"LNG ranks among the most emission-intensive resource themes across the oil and gas sector. Significant emissions are released through the combustion of gas to drive the liquefaction process and any CO₂ removed prior to entering the plant is often vented into the atmosphere.

Measuring emissions is a major challenge, with no consistent definition, methodology or reporting structure in place. And while emissions can be offset in different ways, what’s more critical is the carbon that is measured and included in the first place: deals that have been agreed to date have not applied a consistent approach and have not considered emissions or offset these emissions in the same way.

Over an average cargo life cycle, approximately 270,000 tonnes of CO₂ equivalent is produced, requiring something like 240,000 trees to offset the emissions. This is achievable for a small number of cargoes and currently the cost of these offsetting projects is relatively cheap. But is this achievable across the entire LNG industry? 2019 saw around 5,500 LNG cargoes sold, which would require around 1.5bn trees or carbon credit equivalent. That’s just for a single year’s cargoes: as LNG demand grows, so the number of cargoes, carbon offsets and trees required will also grow."

How trees will respond to rising temperatures is not a settled issue.

Research published in the US in early 2021 noted that forests tend to be darker than other surfaces causing them to absorb more sunlight and retain heat, which is a process known as "the albedo effect."

"We found that in some parts of the country like the Intermountain West, more forest actually leads to a hotter planet when we consider the full climate impacts from both carbon and albedo effects," Prof C.A. Williams said.

Another study by a group of multinational researchers published in January 2021 in 'Science Advances,' analysed more than 20 years of data from about 250 sites that measure the transfer of carbon dioxide between land and plants and the atmosphere. The data show a temperature limit above which trees start to lose more CO₂ than they can take in through photosynthesis. 

"The data show a clear temperature limit, above which trees start to exhale more CO₂ than they can take in through photosynthesis," said co-author Christopher Schwalm to the Inside Climate News Organisation. "The findings mark a tipping point, of sorts, at which “the land system will act to accelerate climate change rather than slow it down,” Schwalm said. 

The study suggests that, by 2040, forests will take up only half as much carbon dioxide from the atmosphere as they do now if global temperatures keep rising at the present pace.

See also a 2020 paper in the journal Nature.

In 2019 scientists at Europe's top technology university, ETH Zürich (Albert Einstein [1879-1955] in 1896-1900 studied at the then Federal Polytechnic School) claimed that the restoration of trees remains among the most effective strategies for climate change mitigation. "We mapped the global potential tree coverage to show that 4.4bn hectares of canopy cover could exist under the current climate. Excluding existing trees and agricultural and urban areas, we found that there is room for an extra 0.9bn hectares of canopy cover, which could store 205 gigatons of carbon in areas that would naturally support woodlands and forests."

A study published in July 2019, led by Thomas Crowther, claimed that once trees had matured, they could store 752bn tonnes of CO₂. Planting trees, the team wrote, is “one of the most effective carbon drawdown solutions to date.”

In October 2019, the journal Science published four highly critical comments. These argued that the researchers had overestimated the carbon trees could store – by a factor of five. They also highlighted multiple mistakes. For instance, much of the land Crowther described as “available” for tree planting already has plants growing on it, all of them storing carbon, many of which would have to be removed, according to Sonia Seneviratne of ETH Zürich and her colleagues.

In 2020 Crowther's team published an extensive correction, in which they admitted that some of their headline claims were "incorrect" and that the data contained "errors."

Reuters in 2019 reported that Czechia's forest owners faced 40 billion crowns ($1.70bn) of damage from an escalating spread of bark beetle. While native to conifer forests, bark beetle has benefited from the dry and hot summer that experts associate with climate change, which has weakened the trees’ natural defences and helped spawn an infestation of the insect. Germany, Austria, Slovakia, France and other European countries.

Why planting tons of trees isn’t enough to solve climate change: Massive projects need much more planning and follow-through to succeed – and other tree protections need to happen too

New forests on grassland release CO₂.

Teagasc, Ireland's agricultural research institute, says Irish agriculture is mainly grassland based, with about 90% of agricultural land under grassland  — by far the highest percentage in Europe. Grasslands are an enormous store of (soil) carbon, but if this land is converted to crop production, some of this soil carbon is released into the atmosphere as a greenhouse gas. "For a range of reasons, much of Ireland’s grassland area is agronomically and economically unsuited to crop production."

Irish grasslands are a significant carbon store, with mineral and peaty agricultural soils under grasslands containing between them over 1bn tonnes of carbon – 500m tonnes is stored in mineral grassland soils and between 500 -700m tonnes in grassland on peat soils.

The institute says that 26.8m tonnes CO₂e (total greenhouse gas emissions) could be allowed by the European Commission as offsetting over the 2021-2030 period.

An Irish solution to an Irish problem or maybe not!!

"However, there are significant challenges in terms of measurement and verification of soil carbon sequestration, particularly in grassland soils, and in terms of the low rates of afforestation over the last number of years, which threatens to considerably reduce the forest C sink."


Methane (CH₄) is far more effective at trapping heat — about 80 times more potent than carbon dioxide and it breaks up in the atmosphere in just about a decade.

The combined percentage of Methane (CH₄) and Nitrous Oxide (N₂O) accounted for 36.1% of Irish greenhouse gas emissions in 2019 and mainly relate to agriculture.

A US study, published in the journal Environmental Research Letters in April 2021, calculated that a full-scale push using existing technologies could cut methane emissions in half by 2030. Such reductions could have a crucial impact on the global effort to limit warming.

Human activity accounts for about 60% of global methane emissions annually, with over a third attributable to the fossil fuel industry. Methane for example is the main component of natural gas and leaks happen while the gas can also result from oil, coal production and shale oil.

 Landfills, emissions from livestock, rice paddies, and manure are also sources.

According to National Geographic, there are 1.4bn cattle in the world, and that number is growing as demand for beef and dairy increases; together with other grazing animals, they contribute about 40% of the annual methane budget.

Another 2021 report recommends feed supplements for cattle to reduce emissions, and reduction in human demand. Reducing emissions from landfills is also important.

"Quick action would help limit dangerous climate feedback loops, while simultaneously delivering important health and economic benefits from reducing tropospheric ozone."

Global rice production emits between 500 and 800m tons of CO₂ equivalent per year, accounting for at least 10% of total agricultural GHG emissions and at least 1% of global GHG emissions. "One of the most promising techniques for reducing rice-related GHG emissions is to reduce or interrupt the periods of flooding."

The world's biggest GHG emitters

Adding Iran and Canada to the 8 countries above (EU27 is regarded as a country) show that the top 10 countries were responsible for 66% of total emissions in 2019.

Data here refer to metric tons of carbon dioxide equivalent (MTCO₂Eq) — that includes CO₂ and the other greenhouse gases. Charts with just CO₂ of course show lower data.

The Group of Twenty (G20) comprise the 19 leading advanced and emerging economies and the EU27. They account for more than 80% of world GDP, 75% of global trade and 60% of the population of the planet.

The G20 is made up of 19 countries and the European Union. The 19 countries are Argentina, Australia, Brazil, Canada, China, Germany, France, India, Indonesia, Italy, Japan, Mexico, the Russian Federation, Saudi Arabia, South Africa, South Korea, Turkey, the UK, and the US.

In 2019 the G20 accounted for 77% of greenhouse gas emissions.

The Rhodium Group, a US independent research firm, says that in 2019, China’s GHG emissions passed the 14 gigaton threshold for the first time, reaching 14,093 million metric tons of CO₂ equivalent (MMt CO₂e). This represents a more than tripling of 1990 levels, and a 25% increase over the past decade. As a result, China’s share of the 2019 global emissions total of 52 gigatons — CO₂ accounted for about 36 GT — rose to 27%.

Rhodium says that in 2019, China’s emissions not only eclipsed that of the US — the world’s second-largest emitter at 11% of the global total — but also, for the first time, surpassed the emissions of all developed countries combined. When added together, GHG emissions from all members of the Organisation for Economic Cooperation and Development (OECD), including all 27 EU member states, reached 14,057 MMt CO2e in 2019, about 36 MMt CO2e short of China’s total.

China’s per capita emissions reached 10.1 tons, nearly tripling over the past two decades. This comes in just below average levels across the OECD area (10.5 tons/capita) in 2019, but still significantly lower than the US, which has the highest per capita emissions in the world at 17.6 tons/capita.

Since 1750, members of the OECD area have emitted four times more CO₂ on a cumulative basis than China

In 2021 the OECD has 38 member countries.

Coal accounts for about 60% of China's energy consumption. However, China accounts for roughly 23% of global renewable energy investment. It is also becoming the largest market in the world for renewable energy. More from the Rhodium Group on climate change.

ABC Australia reports that "China aims to plant trees across an area larger than Belgium each year to increase its forests. Mass planting is part of the country's strategy to bring carbon emissions to net-zero by 2060. By the end of 2025, 24.1% of China's land will be covered by forest, according to officials."

The European Environment Agency (EEA) has produced an interactive data viewer on 2019 greenhouse gas emissions. LU (Luxembourg) appears to have the highest per capita emissions but over 40% of its workforce live outside its borders. EU27 country codes.


The United Nations' World Meteorological Organization (WMO) reported on August 31, 2021, that the number of disasters has increased by a factor of five over a 50-year period, driven by climate change, more extreme weather and improved reporting. But, thanks to improved early warnings and disaster management, the number of deaths decreased almost three-fold.

According to the WMO Atlas of Mortality and Economic Losses from Weather, Climate and Water Extremes (1970 – 2019), there were more than 11,000 reported disasters attributed to these hazards globally, with just over 2m deaths and US$3.64trn in losses. From 1970 to 2019, weather, climate and water hazards accounted for 50% of all disasters, 45% of all reported deaths and 74% of all reported economic losses. More than 91% of these deaths occurred in developing countries (using the United Nations Country Classification).

Last month John Plender noted in the Financial Times that "Governments across the world are urging big investors to galvanise the global corporate sector into meeting climate change goals. A growing number of asset owners and managers have taken their cue and are committing to secure an overall balance between greenhouse gas emissions produced and emissions taken out of the atmosphere — net zero.

Yet in the run-up to November’s COP26 Glasgow climate change summit to accelerate action on the 2015 Paris agreement’s sustainability goals, it is striking how little has so far been achieved. A survey by Energy and Climate Intelligence Unit, a UK non-profit outfit, and Oxford Net Zero, an Oxford university research initiative, has found that only about a fifth of publicly traded companies in the Forbes Global 2000 list has made any form of commitment to net zero."

Last year the Stockholm Environment Institute and Oxfam in a report estimated that the wealthiest 1% of the world’s population was responsible for the emission of more than twice as much carbon dioxide as the poorer half of the world from 1990 to 2015.

Princeton University researchers have found a way to zero in on how dangerously hot the Earth’s tropical zones could become under climate change by looking at the atmospheric dynamics that control the region’s heat and humidity, according to a recent paper in the journal Nature Geoscience.

The researchers found that the “wet-bulb” temperature — a measure of air temperature plus humidity — for the entire tropics is set by the inner workings of the troposphere (the lower atmosphere where weather happens.) A wet-bulb temperature of 35° Celsius (95 degrees Fahrenheit) is considered the upper limit of combined heat and humidity that humans can handle. Beyond that, the body can no longer effectively cool itself via perspiration.

They suggest that heat and humidity in a large portion of the tropics will stay within habitable levels if the increase in global average temperature due to climate change is limited to 1.5℃ or 2 degrees Celsius compared to the past 40 years.

Scientists at the Massachusetts Institute of Technology (MIT) suggest that extremes of weather that persist over long periods are not new and what seems like small changes in average weather global temperatures can have catastrophic regional impacts in some parts of the world — for example before this century ends, areas from North Africa, the Middle East, South Asia (North India, Pakistan and Bangladesh) and China, may become uninhabitable in summer months.

That would result in huge waves of migration. Remember we left Africa in particular when the climate changed.

However, on the bright side, waves of technological advances triggered the Industrial Revolution and haven't stopped despite some people being pessimistic in recent times.

In Squamish, British Columbia, a Bill Gates-backed carbon capture machine is claimed to do the work of 40m trees: youtube

At Arizona State University, the Center for Negative Carbon Emissions, lead by Klaus Lackner, has developed a machine that can capture and store carbon dioxide emissions. It is backed by a Dublin headquartered company Silicon Kingdom; youtube

Given the potency of methane, the US Environmental Defense Fund says "At least 25% of today’s warming is driven by methane from human actions. One of the largest methane sources is the oil and gas industry.... The atmospheric concentration of methane is increasing faster now than at any time since the 1980s."

The EDF says now is the time to tackle methane emissions as the gas is adept at trapping heat.

The International Energy Agency (IEA) representing 30 countries including Ireland that are also members of the OECD, estimates that worldwide, the oil and gas industry can achieve a 75% reduction using technologies available today — two-thirds of it at no net cost.

IEA's Methane Tracker 2021

The UN Food and Agriculture Organisation (FAO) says "Cattle (raised for both beef and milk, as well as for inedible outputs like manure and draft power) are the animal species responsible for the most of these emissions, representing about 65% of the livestock sector’s emissions. Globally, cattle meat production has more than doubled since 1961 – increasing from 28m tons per year to 68m tons in 2014 (Our World in Data).

Landfill, bogs, human and animal waste add to the methane.

The MIT Technology Review says the model used to create the most optimistic scenario in the August 2021 IPCC report, which limits warming to 1.5˚C, "assumes the world will figure out ways to remove about 5bn tons of carbon dioxide a year by midcentury and 17bn by 2100. (The scenario is known as SSP1-1.9, and those figures are based on an analysis of earlier data by Zeke Hausfather, a climate scientist at the Breakthrough Institute and contributing author on the UN assessment.)

That requires ramping up technologies and techniques capable of pulling as much CO₂ out of the atmosphere every year as the US economy emitted in 2020.

"In other words, the world would need to stand up a brand-new carbon-sucking sector operating on the emissions scales of all America’s cars, power plants, planes, and factories, in the next 30 years or so."

*The indicator measures total national emissions of the so-called ‘Kyoto basket’ of greenhouse gases, including carbon dioxide (CO₂), methane (CH4), nitrous oxide (N2O, and the so-called F-gases (hydrofluorocarbons, perfluorocarbons, nitrogen triflouride (NF3) and sulphur hexafluoride (SF6)). Using each gas’ individual global warming potential (GWP), they are being integrated into a single indicator expressed in units of CO₂ equivalents. Emissions data are submitted annually by the EU Member States as part of the reporting under the United Nations Framework Convention on Climate Change (UNFCCC). The average population of the reference year (calculated as the arithmetic mean of the population on 1st January of two consecutive years) is used as the denominator (per capita). The indicator does not include emissions and removals related to land use, land-use change and forestry (LULUCF); it does not include emissions reported as a memorandum item according to UNFCCC Guidelines but does include emissions from international aviation as well as indirect CO₂ emissions.


Irish farming and greenhouse gases: is it time to take the bull by the horns? — Agriculture is the State’s biggest single contributor to greenhouse gas emissions. Over the past decade, the number of dairy cows in Irish milking herds has increased by 45.5%, with a corresponding milk production increase of 60.3%. In 2020 agriculture’s emissions increased by 1.4% —  up 12% in the last 10 years — driven by increased fertiliser nitrogen use (3.3%) and increased numbers of livestock, including dairy cows (3.2%).

Climate perception gaps and individual carbon footprints — The majority of people cannot identify which lifestyle moves are the most effective at limiting their carbon footprint, according to an Ipsos polling survey of more than 21,000 people across almost 30 countries, which was published in 2021. Nevertheless, an overwhelming number claim they know which personal actions they must take to play their part in tackling climate change.

Deaths of 60 million people in Americas in the 1500s and global climate change

Losing Earth: 1979-1989 was the decade climate change was almost stopped - The New York Times' narrative on a missed opportunity: "A broad international consensus had settled on a solution: a global treaty to curb carbon emissions. The idea began to coalesce as early as February 1979, at the first World Climate Conference in Geneva, when scientists from 50 nations agreed unanimously that it was 'urgently necessary' to act."

World Population 1950: 2.6bn 2020: 9.7bn 2030: 8.5bn 2050: 9.7bn 2100: 10.9bn