“You’re off to Dubai, honestly I get confused with this climate field - I’m not sure what the numbers mean.” 🧐 I completely get it. I used to find the numbers overwhelming too. Since then, I’ve spent hours and hours participating in climate courses, reading authoritative science reports 📖 and talking to scientists. And this has helped me put the numbers into context - and translate them into human rights.
I have put together some of the key facts, figures and discussion points so that you can follow COP28 more fully. I start with the basics, and delve into further detail as you come along - so join me below wherever you are on the journey. Plus I’ve inserted some of the more important visuals in this space complete with hyperlinks for more info. You’re welcome!
(Why are human rights relevant for climate I hear you ask? Because we are in a climate emergency. 🛑 The climate crisis is the biggest threat to human rights and humanity of our time. ⏱ Conversely, tackling the climate crisis in a rights-respecting way is the single largest opportunity of our time to fulfil human rights world-wide. 💫 In fact, placing people at the heart ❤️ of climate action is the only way to succeed in the steps ahead for climate action. Companies 🏦 play a pivotal role ⤴ in shaping a rights-respecting future ahead, which includes ensuring the transition is just, equitable and inclusive. ✨You can find out more about all things climate and nature, and its connections to human rights in our content hub which you can subscribe to here).
What are GHGs?
Greenhouse gases (GHGs) trap heat in the earth’s atmosphere. They were a good thing at first, because they helped the earth not get too cold at night by keeping heat in the atmosphere. However, like with all things, moderation is the key! We are creating way too many GHGs and the earth is warming much much too quickly as a result.
Greenhouse gases (GHGs) are gases that trap heat in the earth’s atmosphere.
The sun shines through the earth’s atmosphere in the day, which warms the earth’s surface. At night time, the earth’s surface cools down, and heat is released back into the air. The GHGs in the atmosphere traps some of the heat. This in turn warms up the planet.
Initially, the presence of GHGs was a good thing: it helped us sustain life on earth. If we did not have any GHGs, the earth would be too cold for us to live on it.
However, human activities have dramatically increased the quantity of GHGs being released in the atmosphere. This started during the Industrial Revolution (1850s), and has increased ever since.
The earth’s temperature is increasing so rapidly that we are at a point where climate scientists are questioning whether Earth can continue to sustain life the way it has, in the years to come.
Source: The Council on Foreign Relations, World 101, The Greenhouse Effect (July 2023)
Are all GHGs created equal?
There are a number of GHGs. Some are naturally produced (with their increasing concentration being man-made) - think carbon dioxide (CO2), methane, nitrous oxide, and water vapour. Some are man-made during industrial processes - think fluorinated gases such as . They all differ in how much they influence global warming, depending on how much of its exists in the atmosphere, how long it remains in the atmosphere, and how effective the gas is at trapping heat. Some like carbon dioxide (CO2) are very prevalent and stay for years, while others like methane are less common and don’t last for as long in the atmosphere - but are very potent when it comes to their warming effect.
There are a number of GHGs.
There are a group of gases that are naturally produced - and their increasing concentration in the atmosphere is man-made. These are:
Carbon dioxide (CO2): CO2 is the main GHG due to its prevalence. It is released through the extraction and burning of fossil fuels (e.g. coal, oil, natural gas), from wildfires, and natural processes (e.g. volcanic eruptions).
Methane (CH4): Methane is produced naturally through decomposition. It is released by cattle farming, landfill waste dumps, rice farming and the traditional production of oil and gas.
Nitrous oxide (N2O): Nitrous oxide is produced through the large-scale use of commercial and organic fertilisers, fossil-fuel combustion, nitric-acid production and biomass burning.
Water vapour: Water vapour increases as the earth's atmosphere warms
There are a group of gases (known as fluorinated gases - F-gases) that are man-made during industrial processes:
Hydrofluorocarbons (HFC)
Perfluorocarbons (PFC)
Sulphur hexafluoride (SF₆)
Nitrogen trifluoride (NF3)
How much a GHG influences global warming depends on three factors:
How much of it exists in the atmosphere (its concentration). This is where the ppm abbreviation comes in: concentrations are measured in parts per million (ppm). 1 ppm of one of the GHGs means that there is one molecule of that GHG in every one million molecules of air
How long the gas remains in the atmosphere (its lifetime) and
How effective the GHG is at trapping heat. This is where the GWP abbreviation comes in: each gas has a global warming potential (GWP) which is a measure of the total energy that that gas absorbs over a given period of time (usually 100 years) relative to the emissions of 1 ton of carbon dioxide. For instance, SF₆ has a global warming potential that is 23,000 greater than CO2.
This is also where the concept of the CO2 equivalent (CO2e) comes in. The CO2 equivalent is the metric measure that enables us to compare the emissions from various greenhouse gases on the basis of their global warming potential by converting amounts of other gases to the equivalent amount of carbon dioxide with the same global warming. This metric measure in turn enables us to accurately measure global warming potential. Rises in CO2e tell us more than rises in CO2 since that figure includes all GHGs that are being released, rather than just CO2.
To provide a bit of colour here: Carbon dioxide (CO2) accounts for close to 80% of global human-caused emissions. It stays in the atmosphere for years (40 percent still remains after 100 years, and 10 percent for as long as 10,000 years later). In contrast, methane, accounts for a much lower percentage, but its global warming impact is much higher: almost 30 times greater than that of carbon dioxide over a 100-year period.
We have already warmed the planet by 1.1°C to 1.2°C since the industrial age (1850s). We are aiming to limit the warming to 1.5°C by 2100, so as to avoid catastrophic and irreversible impacts from global warming that occur at every degree of warming past 1.5°C. To achieve this limit on global warming, we need to ensure that GHG emissions (1) peak before 2025 (at the latest), (2) are reduced by close to 50% by 2030 as compared to 2019 levels (43% to be exact), and (3) are not added to the atmosphere by the early 2050s.
Earth has already warmed an average of 1.1 to 1.2 degrees Celsius (1.1°C) since the industrial age (1850s).
Under the 2015 Paris climate agreement, virtually every country agreed to “pursue efforts” to hold global warming to 1.5 degrees Celsius (1.5°C) by the end of the century (2100), as compared to the pre-industrial era.
This number (1.5°C) was agreed because, past this level of heating, scientists find that the impacts of catastrophic heat waves, flooding, drought, crop failures and species extinction will become significantly harder for humanity to handle.
The world’s scientists - as part of the Intergovernmental Panel on Climate Change (IPCC) - have found in their most recent reporting (Sixth Assessment Report, 2021 - 2023) that global average temperatures are already estimated to rise 1.5°C above preindustrial levels sometime around “the first half of the 2030s”
They find that there is one last chance of having a 50% chance of limiting global warming to 1.5°C, and that is if the following steps are taken: (1) GHG emissions need to peak before 2025 (at the latest), (2) GHG emissions need to be reduced by close to 50% by 2030 as compared to 2019 levels (43% to be exact), and (3) no new GHG emissions can be added to the atmosphere by the early 2050s.
If we use the 2°C warming scenario, the figures change as follows: (1) GHG emissions need to peak before 2025 (at the latest), (2) GHG emissions need to be reduced by 25% by 2030 as compared to 2019 levels, and (3) no new GHG emissions can be added to the atmosphere by the early 2070s.
Back in 1990, we emitted 37.9 gigatons of CO2 equivalent in the year. (One gigaton is one billion tons). Every year we have emitted more and more GHGs (except for a dip during the COVID pandemic). In 2022, we emitted 57.4 gigatons of CO2 equivalent in the year.
The world emitted 57.4 gigatons of CO2 equivalent (GtCO2e) in 2022 (UNEP, Emissions Gap Report 2023)
This is a new record of GHG emissions, and it is an increase of 1.2% from 2021 levels
To put this number into context, in 1990, we were at 37.9 gigatons of CO2 equivalent; in 2000 we were at 41.8 GtCO2e; and in 2010 we were at 51.6 GtCO2e and in 2020 we were at 54.5 GtCO2e. We emit close to 17 gigatons more of GHG into the atmosphere, as compared to what we were emitting 30 years ago
How much carbon do we have left to emit, aka what is our carbon budget?
We only have a limited amount of GHG emissions left to emit before we reach a global warming threshold of 1.5°C, or 2°C. The lower we want to keep the temperatures, the less carbon we can emit and the lower our carbon budget needs to be. The most recent scientific figures, updated with the warming that happened in 2022, show us that we have a remaining carbon budget of 250 gigatons of CO2 equivalent. This is less than five years of current CO2 emission (57.4 gigatons of CO2 equivalent in 2022). This means that we will have exhausted our current carbon budget by around 2028, committing the world to warming of 1.5°C above preindustrial levels - if we continue with the current levels of GHG emissions.
A carbon budget (also known as the carbon dioxide emission budget) is the cumulative amount of carbon dioxide emissions permitted over a period of time to keep within a certain temperature threshold - 1.5°C, or within 2°C.
Global warming is proportional to the total net amount of CO2 that has ever been emitted into the atmosphere from human activities.
Therefore, limiting global warming to a specified level requires the total amount of CO2 emissions ever emitted be kept within a finite carbon budget.
The lower we want to keep the temperatures, the lower our carbon budget needs to be.
The carbon budget will continue to be depleted with each passing year - until global CO2 emissions reach net-zero levels.
In 2020, the IPCC calculated that we have a remaining carbon budget of 500gigatons of CO2 equivalent (GtCO2e) (for a 50% chance of limiting global warming to 1.5°C from 2020 onward), or of 1,150 GtCO2 (for a 67 per cent chance of limiting warming to 2°C). (IPCC AR6)
This figure has since been updated with the additional carbon budget used until 2022. We now have a remaining carbon budget of 250gigatons of CO2 equivalent (GtCO2e) (for a 50% chance of limiting global warming to 1.5°C from 2020 onward), or of 1,200 GtCO2 (for a 50 per cent chance of limiting warming to 2°C). (2023 study led by Imperial College London researchers and published in Nature Climate Change available here).
We now know that the emissions for 2022 were of 57.4 gigatons of CO2 equivalent. Therefore, the remaining carbon budget of 250gigatons of CO2 equivalent is less than five years of current CO2 emission.
This means that we will have exhausted our current carbon budget by around 2028, committing the world to warming of 1.5°C above preindustrial levels - if we continue with the current levels of GHG emissions.
This depends a little on what you are counting: emissions can be measured (1) country by country, in absolute terms, (2) by calculating per capita - based on an average of emissions per person in a country, (3) between people within the same country and (4) counting emissions starting in 1850 (taking a historic perspective).
Collectively, the G20 currently account for 76 per cent of global emissions (UNGP 2023). GHG emissions across the G20 also increased by 1.2 per cent in 2022. The members of the G20 are Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the U.K. and the U.S., as well as the European Union
There were increases in in China, India, Indonesia and the United States of America. There were decreases in Brazil, the European Union and Russia.
The diagram below depicts the GHG emissions per country, with China, USA and India leading the chart. When calculating per capita, the USA overtakes China as the top emitter.
GHG emissions per capita vary significantly across countries:
The world average of per capita emissions is 6.5 tons of CO2 equivalent (tCO2e)
The average for G20 is 7.9 tons of CO2e. It is 2.2 tons of CO2e for least developed countries. It is 4.2 tons of CO2e for small island developing States.
GHG emissions per capita vary significantly within the population:
The 10 per cent of the population with the highest income accounted for nearly half (48 per cent) of emissions
Two thirds of this group living in developed countries
The bottom 50 per cent of the world population contributed only 12 per cent of total emissions.
GHG historic emissions are unequal:
Nearly 80 per cent of historical cumulative fossil and LULUCF CO2 emissions came from G20 countries
The largest contributions came from China, the United States of America and the European Union
The least developed countries contributed 4 per cent
The United States of America account for 4 per cent of current world population, but contributed 17 per cent of global warming from 1850 to 2021, including the impact of methane and nitrous oxide emissions.
India, by contrast, accounts for 18 per cent of the world population, but to date only contributed 5 per cent of warming.
The following sectors emit the most GHGs: Energy supply (20.9 GtCO2e; 36 per cent of the total), Industry (14.4 GtCO2e, 25 per cent of the total), Agriculture and land use, land use change and forestry (10.3 GtCO2e, 18 per cent), transport (8.1 GtCO2e, 14 per cent) and buildings (3.8 GtCO2e, 6.7 per cent).
Emissions can be split into five major economic sectors:
Energy supply
Industry
Agriculture and land use, land use change and forestry (referred to as LULUCF)
Transport
Buildings
When it comes to energy (UNEP 2023 figures):
In 2022, energy supply was the largest source of emissions at 20.9 GtCO2e (36 per cent of the total)
This is mainly due to combustion emissions in the power sector (14.8 GtCO2e) and emissions from fossil fuel production including fugitive methane (6.1 GtCO2e).
The energy supply sector is the largest contributor to the increase in emissions over the past decades, largely due to the worldwide expansion of coal- and gas-fired power generation.
The energy sector is also one of the only sectors where some countries have made progress in reducing emissions by switching to lower emission fuels and by scaling up renewable sources.
The coal, oil and gas extracted over the lifetime of producing and under-construction mines and fields, as at 2018, would emit 936 gigatons of CO2 if fully used – around 3.5 times the carbon budget available to limit warming to 1.5°C (with 50 per cent probability)
Carbon budgets aligned with the long-term temperature goal of the Paris Agreement require that much of the existing capital stock will need to be retired early, retrofitted with carbon capture and storage, and/or operated below capacity.
Industry is the second largest sector when accounting by direct emissions (14.4 GtCO2e, 25 per cent of the total), followed by agriculture and LULUCF CO2 (10.3 GtCO2e, 18 per cent), transport (8.1 GtCO2e, 14 per cent) and buildings (3.8 GtCO2e, 6.7 per cent).
A few notes:
All sectors have fully rebounded from the drop in emissions induced by the COVID-19 pandemic and now exceed 2019 levels - except for transport
Global primary energy consumption expanded in 2022 – an expansion mainly met by a growth in coal, oil and renewable electricity supply. Governments still plan to produce more than double the amount of fossil fuels in 2030 than would be consistent with the long-term temperature goal of the Paris Agreement.
CO2 emissions from fossil fuel combustion and industrial processes were the main contributors to the overall increase, accounting for about two thirds of current GHG emissions.
Emissions of GHG emissions that have higher global warming potentials and account for about one quarter of current GHG emissions, are increasing rapidly. These are methane (CH4), nitrous oxide (N2O) and fluorinated gases (F-gases).
Global net land use, land-use change and forestry (LULUCF) CO2 emissions remained steady in 2022.
