A key feature of the climate report is the abundance of acronyms, and the title for today’s post is a deliberate attempt to introduce a couple of them!
One of the goals for establishing a model framework is to forecast. And the prerequisite for reliable forecasting is a good fit with the historical data. We have seen in the previous post the importance of CMIP and the role of climate models to match the historical trends as much as possible.
SSPs
This projection of future scenarios is based on fives pathways, called Socioeconomic Pathways (SSP) – SSP1 through SSP5. These range from the mildest (impact to climate change) SSP1 (sustainable development) to the harshest SSP5 (high energy demand, fossil fuel development). These pathways are then combined with the global effective radiative forcing (ERF) values (W/m2) envisaged in 2100 to get the SSP matrix.
Representation of SSP scenarios
An SSP scenario is represented by the SSP pathway number followed by the 2100 forcing value. For example, the sustainable pathway at 1.9 W/m2 ERF is SSP1-1.9. Chapter 4 of the WG1 report of AR6 focusses on 5 scenarios SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5.
As per these scenarios, a 1.5 C increase of global mean surface air temperature (GSAT) is highly likely to occur in SSP5-8.5, likely to occur in SSP2-4.5, SSP3-7.0 and more likely than not in SSP1-1.9, SSP1-2.6 in the next 20 years!
The backbone of the IPCC climate assessment is the Coupled Model Intercomparison Project (CMIP). The term coupled means that the model can evaluate the whole system, i.e., atmosphere and ocean. Intercomparison suggests that climate models, developed by various groups at different points in time, are harmonised using the same set of inputs (provided by CMIP). This way, if there are differences between models’ predictions, it can be assured that it was not due to variations in experimental design but due to the difference in physics or the mathematical treatments.
Climate models are mathematical representations of complex geo-chemical-physical aspects and relate various inputs to the observed features of global warming. It gives better control over the underlying science but more importantly, it serves as a framework for forecasting.
The tool, currently at version 6, is a collaborative framework aiming to improve the understanding of climate changes related to global warming. The tool compares climate models, developed by various groups, with the experimental data and to each other.
The multi-model mean captured by CMIP6 closely matches the Global Mean Surface Temperature (GMST), although there can be differences in the predictions of individual models with the observed data.
We may divide the ecological system we reside in into four parts viz., atmosphere, biosphere, cryosphere and oceans. The climate report makes an exhaustive list of evidence of changes in these sub-systems. Some of them, such as the rise in sea levels and the increased frequency of floods, prove direct evidence for a changing climate, whereas the others, e.g. temperature rise or elevated levels of greenhouse gases in the atmosphere, are evidence of its root causes.
Data from atmosphere
The first and foremost is the carbon dioxide (CO2) in the atmosphere. Its concentration had reached 409.9 (+/- 0.4) ppm in 2019. Similar values for the other greenhouse gases (GHG) were methane 1866.3 +/- 3.3 ppb and nitrous oxide 332.1 (+/-0.4) ppb. This level of CO2 is the highest in the last two million years! These molecules are ominous for the system because of their power to influence the so-called Effective Radiative Forcing (ERF); the subsequent increase of energy causes warming in the system.
Data from biosphere
Global Mean Surface Temperature (GMST), the poster boy of climate change crisis, has increased by over 1.09 oC [0.95 – 1.20] since industrialisation; 1.59 oC for land and 0.88 oC for oceans.
Global land-precipitation has increased since 1950, and its pace has further picked up since the 1980s.
Data from cryosphere
The annual mean and the late-summer values of Arctic ice coverage are the lowest since 1850. The decadal means of Arctic sea ice area has decreased from 6.23 million km2 in the 1980s to 3.76 million km2 in the last decade for September and from 14.52 to 13.42 million km2 for March.
Data from oceans
The global mean sea level (GMSL) has risen by 0.2 m since 1901, and the rate is accelerating. On the other hand, the ocean heat content has increased, pH and oxygen contents have decreased.
The first two Working Group (WG) reports of the sixth assessment (AR6) of the Intergovernmental Panel on Climate Change (IPCC) is now available for public view. Two more reports – the third working group (WGIII) and final synthesis report (SYR) – are due later this year.
IPCC and working groups
IPCC, formed in 1988 by World Meteorological Organization (WMO) and United Nations Environment Programme (UNEP), is the United Nations (UN) body for assessing the science related to climate change. The body has done an honourable job for more than 30 years in providing policymakers with scientific information about climate change. While IPCC does not conduct its research, it gathers input from thousands of scientists and mathematicians working in this field globally and facilitates expert review.
It has three working groups and a task force. WGI deals with the science of climate change, WGII its impact and the third group, WGIII, concerns the mitigation plans.
Assessment cycles
The current assessment cycle, the sixth, started from where the fifth had ended (2013-14) and has its first report (AR6-WGI) released in 2021.
WGI: physical science basis of climate change
Through its 12 chapters spread over 4000 pages, the report summarises the current state of knowledge about climate information and human-induced climate change. We’ll go through some of its findings in the next post.
2015 was a landmark year for international policymaking. The year started with the United Nations Sustainable Development Goals (SDG) and ended with the climate goals, known as the Paris Agreement.
While 17 goals constitute the SDG, we focus on the first one i.e., No poverty in all its forms everywhere. Extreme poverty per the international poverty line (IPL) stands at USD 1.90/day. The World Bank presented two additional levels at USD 3.20/day and USD 5.50/day. It means getting people out of these should be the priority of the rest of us.
Contradicting goals
At first sight, you may find a contradiction between these two goals. It is well known that carbon dioxide emissions increase with wealth (consumption), and targetting SDG1 flags an inconvenient truth of raising it further.
Asymmetry in emissions
A paper published last week (14/Feb/2022) in Nature Sustainability addresses this problem. The work computes the potential CO2 emissions due to the upliftment of masses from absolute poverty and proves that the increase is negligible in comparison with the total. The reason lies in the asymmetry of emissions between the rich and the poor. Let’s understand the math behind the claims.
In 2017, 9.2% of the global population lived in extreme poverty of less than USD 1.90/day, and their average footprint is 0.4 tCO2 (per person per year). Another 14.9% live between 1.90 and 3.2 USD/day. They contribute around 0.6 tCO2. The last batch includes about 19.5% of people who live between 3.2 and 5.5 USD/day and at 0.9 tCO2/person/year. To put these numbers in perspective, see the following:
CO2 Footprint (tCO2/person/yr)
Global Average
4.5
US Average
14.5
top 10% US
54.9
Europe Average
6.3
Imagine we aim to lift the people in 1.90 (0.74 Billion) and 3.2 (1.2 Billion) USD/day bracket to 5.5 (1.6 Billion). It would mean 3.5 billion people in the USD 5.5 per day category with an average footprint of 0.9 tCO2. So the current emissions from the 3.5 billion = 0.74 * 0.4 + 1.2 * 0.6 + 1.6 * 0.9 = 2.46 GtCO2/yr. The new emissions (after 1.9 and 3.2 are raised above the 5.5 mark) = 0.74 * 0.9 + 1.2 * 0.9 + 1.6 * 0.9 = 3.19 GtCO2/yr. The difference = 3.19 – 2.46= 0.73 GtCO2/yr. The additional emissions, 0.73 is about 2% of the current global emission of 36 GtCO2/yr. And they live in India, China, Sub-Saharan Africa and South and Southeast Asia.
Here is an update on the global carbon dioxide (CO2) situation. If you need a background on the topic, you may go to my previous posts on this topic. The world needs to restrict the average temperature rise, from the pre-industrial level, to below 1.5 oC to avert catastrophic climate changes. For simplicity, take 1850 as the start of the counting. 1.5 oC corresponds to a median concentration of CO2 of about 507 ppm (parts per million) in the atmosphere (425-785 ppm at 95% confidence range).
From these numbers, one can estimate the quantity of CO2 we could throw into the atmosphere before it crosses the critical concentration. The maximum remaining quantity of CO2 is known as the Carbon Budget.
Now the numbers: Based on the latest estimate at the beginning of 2022,
Item
Quantity
Unit
Carbon Budget
420
GtCO2
CO2 Concentration
414.7
ppm
Global anthropogenic CO2 emissions (2021)
39.4
GtCO2
Global fossil CO2 emissions (2021)
36.4
GtCO2
Gt = Gigatonne = billion tonnes; anthropogenic = originating from human activity; 39.4-364. = 3GtCO2 comes from land usage
Spending Wisely
At the current rate, the budget will be over by 2032! There is a resolution from the global fraternity to reduce the net CO2 emission to zero by 2050. If we trust that commitment, one can draw spending scenarios to reach the target. If we spend the remaining 420 Gt in equal chunks, we can do it by spending 15 Gt every year until 2050 and put a hard brake, which is not practical, given the present lifestyle of 36.4 Gt/yr. Another scenario is by reducing 8% every year. Notice that an 8% yearly reduction corresponds to halving every nine years. In other words, the spending in 2030 has to be half of what we did last year.
And How are we doing?
Nothing to cheer about (so far). The emission figures from the last three years have been:
Year
Total CO2 Emitted (GtCO2)
at 8% reduction (GtCO2)
2019
36.7
36.7
2020
34.8
33.8
2021
36.4
31
Since we know the real reason for the decline in 2020, the global shutdown due to pandemic, the 8% reduction remains a project without any evidence of progress.
Industrial melanism is a term to familiarise. Biston betularia, the “poster moth” of evolution through natural selection, made this word immortal. You may call it a victim of the Industrial Revolution (or the coal pollution of England). However, the transformation of this humble creature provided the most powerful illustration of the theory of evolution and accelerated its inevitable journey towards becoming a theorem.
To give a brief background: Biston betularia is a type of peppered moth that had transformed from its pale (typica) form to black (carbonaria) in the last decades of the nineteenth century, coinciding with the industrial revolution in England. The hypothesis for the observed shift is that the pale varieties became prey to the bird predators as the former had become easily distinguishable on the blackened walls of industrialised cities of England, thanks to the coal revolution (and pollution). Accidental mutant varieties with black shades saved themselves from the lookout of the predators and became the most abundant species in the 20th century and continued until a few decades ago.
We have seen it before but repeating. Polymorphism is where two individuals differ in their DNA sequence, and the less common variant is present in at least one per cent of the people tested. The simplest type of polymorphism is when there is a single-letter change in a genetic sequence. That is called a Single Nucleotide Polymorphism (SNP).
Scientists have recently discovered the locations (the sequence and the genes) of the mutations that caused the change of colour from pale to dark. Further, analysis by statistical inference has found that the transposition happened around 1819, consistent with the actual observation of the change (from the dominance of the pale population to the black).
Noone sees its evolution!
The story of the peppered moth’s evolution is both fascinating and confusing. First, we need to realise that an individual white moth never transforms into a back one in its lifetime; the celebrated illustration (The Road to Homo Sapiens) of Rudolph Zallinger may tell you otherwise. It was a crime, though unknowingly, the artist committed against science that etched this faulty image – of an ape transforming into an upright man – permanently into the human psyche. Evolution is not a conscious conversion of one species to another. For example, the original white-moth-dominated society and the new black-dominated can easily have a hundred generations of separation.
Humans, the moths of glass sponges
We can see a moth’s evolution in front of us because a moth has a short lifetime – a few months at the maximum. In other words, given a few decades, we could see a few hundred life cycles of moths. Human evolution is not visible to humans because we can never see a thousand generations of ourselves unfolding before us. That is why we go after evidence, and science delivers. In doubt, ask a glass sponge who has survived this planet for 10,000 years!
The industrial melanism mutation in British peppered moths: Nature
In an ideal world, our activities should result in about 2 tonnes of CO2 emissions per person per year, but in reality, it is 70 tonnes for the top 1% and less than 1 for the bottom 50%
The new Oxfam report starkly reminds us of the global disparity in consumption-based CO2 emissions and how the Paris Effect may impact the low-income 50%. The report presents a collection of data and future realisations, but I will not go through all of them.
In one of my previous posts, I commented about the present total CO2 emissions, around 47 billion tonnes in 2018 (Gt/yr). Oxfam report estimates the consumption-based emission to be about 35 Gt in 2015. The emission ratewe need to target for 2030 is 18 GtCO2 to stay on course with the 1.5 oC target. Before we jump into the report details, take a stop for a quick recap of climate targets.
The global mean temperature has now reached about 1 oC above the pre-industrial level; the world needs to keep its peak to about 1.5 oC to manage catastrophic climate change. In other words, the world can only emit a total of 420 – 580 Gt, as per the IPCC special report (SR 15), which is already three years old! So what remains with us to spend from today is less than 500 billion tonnes (carbon budget). There are different pathways to achieve the goal, and one of them is to cut the emissions by half by 2030 and net-zero emissions by 2050.
Back to the report: today’s total global consumption-based carbon emission is 35 GtCO2 – 17 from the top 10%, 15 from the middle 40% and a mere 3 from the bottom 50%! The per capita emissions are
21 tonnes per person for top 10%
5 tonnes per person for middle 40%
< 1 tonne per person for bottom 50%
Note that the top 10% is already trending at the total target of 2030 (18 GtCO2). The report estimates the expected reduction of the richest and the middle to be about 10%, which is much lower than the 90% and 57% required to reach parity (everyone shares the same per capita emissions).
The Paris Effect and its gaining traction in the developed world can lead to another moral failure of the equity principle. As we have seen in the distribution of COVID-19 vaccines, the morally agnostic twins, capitalism and technology, parented by populism and mistrust, will again fail to support the marginalised. Forcing emission cuts across the board will disproportionately impact the poor and widen the existing wealth and opportunity gaps. There must be additional climate finance, with a fair share from the top emitters, not just countries but also individuals beyond borders, to support the lower and middle-income groups to achieve the climate targets. Innovators, especially from the developing world, should also use this opportunity and focus more on inclusive low-carbon technologies.
“That is the question. Whether ’tis easier to ignore and suffer The heat and cold of unpredictable future Or to put life and money against the unwavering force, And make a chance for my past to redeem?”
– a poor adaptation of Shakespeare’s Hamlet
What is decarbonisation?
Decarbonisation is the process of reducing human-made greenhouse gas (GHG) emissions. Based on scientific evidence, there are a bunch of gases in the atmosphere that can cause what is known as global warming. Out of these gases – carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) – CO2 accounts for more than two-thirds.
Why do we need to change?
Global warming, or the steady increase of mean global temperature, is well established and has been very dramatic since the early last century. GHG plays a pivotal role in warming and the associated changes in weather patterns (known as climate change). It is well-established by observations and through various climate models. The plot below shows the mean change in global temperature since 1880 (taken from NASA’s Global Climate Change page).
As per ClimateWatch, human activities are responsible for about 47 billion tonnes of CO2 equivalent in 2018, and 34 billion (73%) of it is from the energy sector. The remainder is predominantly agriculture and land usage.
Who can make a difference?
While the world needs to unite to manage GHG emissions, three sectors in the energy bucket hold the key to success. The top three sectors that account for approximately 80% of the energy consumers are industry (29% or 120 million TeraJoules), transportation (29%) and residential (21%) (based on 2019 data from the International Energy Agency (IEA)). Carbon-based fuels (oil, gas and coal) supply 80% of this energy.
How can we change?
There are a few options ready in the development funnel. The first one is using electricity as the primary vehicle for energy supply. And the electricity may come from renewables (wind, solar, hydro, geothermal), nuclear, and even carbon-based fuel with carbon capture and storage. The last option may work during transition, with a systematic plan to move away. Wherever storage is required, batteries and hydrogen (produced from water and electricity) come in handy.
What are the challenges?
The first one that comes to mind is cost, especially for the industrial and transportation sectors. The fundamental driver for it to change is when the replacement’s total cost (capital and operation) is lower than the operating cost of the existing technology. Costs usually come down when there is production on a sufficient scale. However, here is a chicken and egg problem – higher costs prohibit the scale, and costs can not come down when the scales are low; it is the right time for the government to intervene through mandates and incentives.
Then comes infrastructure and affordability for electrification; both affect the transportation sector. The easy part is to produce electricity, followed by storage. Batteries help smaller vehicles but not the larger ones – the trucks, ships and aircraft. So, you require a different solution. The transformation of smaller vehicles also has its challenges. How will you provide incentives to a billion pieces of equipment spread all over the planet – be it charging points or simply the financial means to procure an electric vehicle?
The last sector is residential. You may think it was the easiest to change based on the public outcry to stop global warming. I will argue that it is the most difficult to change. First, like the case with cars, buildings are spread all over the world. Unlike automobiles, they are more expensive to change and even more difficult to convince that part of the problem is just in my backyard.
