In this article, we will take an in-depth look at the current state of CO₂ levels in the atmosphere, examining a concerning trend that contradicts expectations and its impacts. Over the past few decades, there has been growing hope that CO₂ concentrations would begin to decrease, thanks to global efforts. However, the latest data from the Mauna Loa Observatory in Hawaii, where atmospheric CO₂ has been measured for more than 60 years, reveals a crucial trend: rather than declining, CO₂ levels are accelerating at one of the fastest rates ever recorded.
This sharp rise in greenhouse gases is driving global temperatures up, with the current warming already reaching 1.3°C above pre-industrial levels. The urgency is clear: to limit global warming to 1.5°C, as outlined in the Paris Agreement, the accumulation of CO₂ and other greenhouse gases must not only be halted but also reversed.
In this article, we will analyse the following factors:
- Status of CO₂ emissions and concentrations
- Fossil CO₂ emissions in major countries
- The role of natural carbon sinks and their weakening
- The global carbon budget
- Prospects and mitigation strategies
1. Current status of CO₂ emissions and concentrations
1.1 Recent data and trends
The data gathered over the past few years paints a concerning picture, with not only atmospheric CO₂ concentrations continuing to rise, but also the rate of this rise accelerating at an alarming pace.
The Mauna Loa Observatory in Hawaii has been monitoring CO₂ levels since 1958, and the iconic Keeling Curve (below) illustrates this dramatic trend.
In 2024, the annual rise in CO₂ at Mauna Loa reached a record 3.58 parts per million (ppm), the fastest on record. This rapid increase mirrors a similar rise in global CO₂ levels, which, according to satellite data, increased by 2.9 ppm in 2024—marking the second-largest increase on record after 2015-2016.
Analysing the latest report from the Global Carbon Project, it highlights the scale of the challenge: global CO₂ emissions from fossil fuels and cement have increased by 0.8% in 2024, reaching a new high of 37.8 billion tonnes of CO₂ (GtCO₂). This is 0.6 GtCO₂ higher than the previous record set in 2023. When considering total emissions—including both fossil fuels and land-use emissions—the figure rises to 41.6 GtCO₂, reflecting a 2% increase compared to 2023.
The 2024 figures show a slower growth in fossil CO₂ emissions compared to the previous decade, driven by the transition to renewable energy sources and a decrease in coal use. However, land-use emissions have decreased slightly, helping to offset some of the fossil fuel emissions. Despite these efforts, the required rapid and deep reduction in emissions to stabilize global temperatures remains elusive.
As we examine the data further, we will explore visual comparisons that illustrate how current CO₂ levels compare to the scenarios projected by the IPCC. These comparisons highlight the vast gap between where we are today and where we need to be to avoid catastrophic climate impacts.
1.1 Comparison with IPCC projections
The third working group report of the IPCC’s Sixth Assessment Report (AR6), published in 2022, outlined several “illustrative pathways” that provide a roadmap for how different mitigation strategies could shape future greenhouse gas emissions and global temperatures.
Among the most optimistic scenarios are the “Shifting Pathways” (IMP-SP), “Low Demand” (IMP-LD), and “Renewables” (IMP-Ren). These pathways illustrate how different mitigation efforts could limit global warming to 1.5°C or slightly exceed it before returning below the threshold in the following decades. Each scenario focuses on different strategies for emission reductions and energy transitions:
- Shifting Pathways (IMP-SP): Focuses on broader sustainable development, addressing inequality and phasing out fossil fuels.
- Low Demand (IMP-LD): Prioritizes energy demand reduction, along with a gradual phase-out of fossil fuels.
- Renewables (IMP-Ren): Envisions a future heavily reliant on renewable energy sources.
As shown in the table below, the buildup of atmospheric CO₂ in these pathways slows significantly compared to the average rate of 2.41 parts per million (ppm) per year observed in the 2010s. Specifically, the growth rate drops to between 1.33 and 1.79 ppm per year in the 2020s, with a subsequent decline in CO₂ concentrations expected to begin in the 2030s or 2040s, ultimately reducing atmospheric CO₂ levels.
From analyzing the table and the three scenarios presented, the Low Demand (IMP-LD) pathway has the most significant impact on reducing atmospheric CO₂ levels. This scenario focuses on energy demand reduction and achieving such goal is made possible through advancements in more efficient production technologies, energy management systems, and in technologies to enhance an efficient use of energy.
Exergy’s ORC technologies for heat recovery in industrial and oil & gas sector, and industrial heat pumps are key contributors to this effort. By optimizing energy use, it is possible to achieve substantial cuts in emissions. For example, in 2024 Exergy’s operational power plants have saved the emission of 1,200,000 tons of CO2.
2. Fossil CO₂ Emissions in Major Countries
Global fossil CO₂ emissions, including those from coal, oil, gas, and cement, have risen by 0.8% in 2024, setting a new record and surpassing pre-Covid levels. China remains the largest emitter, contributing 32% of global emissions, with a slight increase of 0.4 % in 2024 due to rising natural gas emissions. The U.S. accounts for 13% of global emissions, showing a small decrease driven by lower coal emissions and rising electric vehicle adoption. The EU, representing only 7% of global emissions, registered 2.2% reduction in CO2 in 2024, fuelled by clean energy adoption and high energy prices. Meanwhile, emissions in India have risen by 5.3%, largely driven by increasing energy demand from coal and natural gas. Despite rapid expansion of renewable energy in India, it still lags behind the pace of power demand growth. The rest of the world, excluding international aviation and shipping, is responsible for 38% of global emissions, with emissions increasing by 1.1% in 2024. These trends highlight the uneven progress among major emitters in reducing CO₂ emissions and underscore the need for continued global cooperation and action.
3. The role of natural carbon sinks and their weakening
Oceans, forests, and soils are key players in absorbing CO₂ from the atmosphere, acting as natural carbon sinks that help offset greenhouse gas emissions. Forests capture carbon through photosynthesis, storing it in trees and soil, similarly oceans absorb a large portion of CO₂, either in marine ecosystems or dissolved in seawater. Soils also act as significant carbon reservoirs. However, due to rising temperatures, deforestation, ocean acidification, and land degradation, these carbon sinks are becoming weaker and less efficient.
One significant factor behind the record rise in global CO₂ emissions in 2024 was the weakening of land carbon sinks. This allowed more CO₂ to stay in the atmosphere. El Niño conditions in the first part of the year contributed to this, as they caused hotter, drier weather in many tropical regions. These conditions led to weaker vegetation growth and more carbon release from decaying soils and wildfires, reducing the ability of land ecosystems to absorb CO₂.
With El Niño fading and La Niña conditions taking over, land carbon sinks are expected to recover somewhat. This is why we predict a slower CO₂ rise between 2024 and 2025 than between 2023 and 2024, with an estimated increase of 2.26 ppm.
The weak land carbon sinks in 2023, partly due to extreme global temperatures, were further impacted by even hotter conditions in 2024. This was the first year in which global temperatures exceeded 1.5°C above pre-industrial levels.
As global warming continues, extreme temperatures will become more frequent and intense, leading to stronger effects on the carbon cycle. If land carbon sinks weaken more than expected, it will make it harder to slow the rise in atmospheric CO₂. Monitoring the global carbon cycle will help determine if this trend continues.
4. The global carbon budget
The Global Carbon Project annually provides an estimate of the global carbon budget, which tracks CO₂ emissions from human activities and their absorption by oceans and land. The most recent budget, including estimates for 2024, is represented in the accompanying figure. Positive values indicate CO₂ sources, such as fossil fuels and industry (dark blue) and land use (mid blue). Negative values represent carbon sinks, with the oceans (light grey) and land vegetation (mid grey) absorbing CO₂. The remaining CO₂, not absorbed by these sinks, accumulates in the atmosphere (dark grey).
From 2015 to 2024, the oceans have absorbed about 26.5% of total human CO₂ emissions, equating to approximately 10.6 GtCO₂ per year. However, the ocean’s capacity to act as a CO₂ sink has stabilized since 2016, following rapid increases in previous decades. This change reflects the leveling off of global emissions over that period.
The land sink, which accounts for around 29% of global emissions absorbed (approximately 11.5 GtCO₂ annually), saw a significant drop in effectiveness in 2023, prompting concerns about its potential collapse. However, with the fading of El Niño conditions, the land sink has largely recovered in 2024, returning to its typical absorption rate over the past decade.
Meanwhile, CO₂ emissions from wildfires were notably high in 2024, reaching about 7 GtCO₂ during the first ten months of the year—similar to the above-average levels seen in 2023. The majority of these emissions were driven by large fires in North and South America, especially in Canada and Brazil. It is important to note that fire-related CO₂ emissions are reflected in both land-use emissions and the land sink, making it difficult to directly compare them to other components of the carbon budget.
Despite the ongoing role of natural carbon sinks, the overall trend remains concerning. Human-driven CO₂ emissions continue to outpace the planet’s ability to absorb them, leading to a steady rise in atmospheric CO₂ levels.
5. Future prospects and mitigation strategies
Looking ahead, these trends highlight the urgent need for substantial emission reductions and enhanced efforts to strengthen natural carbon sinks. Without significant action, future increases in CO₂ levels may continue to accelerate, pushing global temperatures higher and increasing the challenges in meeting climate goals. The path forward requires rapid and sustained global cooperation to stabilize atmospheric CO₂ and mitigate the impacts of climate change.
Building a comprehensive carbon mitigation strategy requires considering various factors, recognizing the need for a diversified approach based on industry, countries, and available resources, while ensuring harmonization.
In general, mitigation strategies that enhance and accelerate emission reductions should focus on:
- Significant investments in clean energy innovations to decarbonize power generation, heating and the mobility sector
- A faster phase out of coal, oil and gas fossil fuels
- Implementation of long-term policy frameworks that enable all governments and stakeholders to plan for change. These long-term objectives should be tied to measurable short-term targets and policies to track progress and stay on course with long-term goals
- Policies designed to unlock new business models and attract more private finance, especially in emerging economies
- Stronger international co-operation addressing global challenges through coordinated actions that cross borders
Conclusion
In conclusion, addressing the climate crisis requires urgent and coordinated action at both global and local levels. Global policies, such as the Paris Agreement, are essential, but international cooperation must go beyond formal commitments, with each country playing its part in concrete and timely actions. Mitigation strategies must be both practical and scalable. Urgent solutions like reforestation, sustainable land management, clean energy technologies innovation and renewables deployment are vital to reducing CO₂ emissions. Moreover, as highlighted in the pathways, reducing energy demand plays a crucial role in achieving substantial emissions reductions. Focusing on energy efficiency is key to reducing CO₂ levels. Constant monitoring of CO₂ concentrations is also essential to track progress and prevent exceeding critical thresholds.
If you are an industry player looking to contribute to CO₂ reduction goals and explore technologies to cut emissions, Exergy offers solutions to reduce emissions from heat production and waste heat recovery. Join us in adopting innovative, sustainable technologies to make a real impact on the environment.
For more information, contact us here.
Let’s partner together!
Resources:
