Is 1.5C the correct way to measure climate change?

The year was 2015. In the halls of Le Bourget in Paris, something profound was about to unfold. The whole world was watching in anticipation. Politicians, oil company representatives, and climate activists were all present, their eyes fixed on the stage for the closing remarks of COP21. As the anticipation built, Mr. Laurent Fabius, the foreign minister of France and chairperson for COP21, stepped forward to present the meeting's conclusions. 

"The world shall limit its carbon emissions to ensure a 1.5°C target by 2050." - he declared, his words echoing through the room. **

Silence. 

Then a huge cheer erupted; there were celebrations all around. Activists beamed with hope, envisioning a future where the air would be cleaner, pollution non-existent, and companies and governments would finally take concrete steps to reduce their emissions. It seemed as though humanity had finally turned the corner on climate change.

-and they lived happily ever after. 

Cut to 2024, nearly a decade after that historic announcement. I'm afraid it is time to shatter the illusion, and it is not a fairy tale. 

The Limitations of the 1.5 °C Target

Paris Treaty 2015
Leaders celebrating the Paris Agreement at COP21, marking a pivotal moment in the global fight against climate change. Source: UN Climate Action

 

The Intergovernmental Panel on Climate Change (IPCC) has long emphasized the importance of limiting global warming to 1.5°C above pre-industrial levels, to mitigate the worst impacts of climate change. This was adopted by 196 parties in the COP21 that took place in Paris. While this goal was well-intentioned and backed by science, it has a significant flaw: choosing the value of 1.5°C as the target threshold. 

The 1.5°C target was set to ensure that the planet avoids the most catastrophic consequences of climate change. However, the choice of this specific value has been criticized for its arbitrariness. Prominent Scientists like Sergey Paltsev (Deputy director of MIT’s Joint Program on the Science and Policy of Global Change) have acknowledged that the 1.5°C target is not a precise scientific threshold and the devil, is actually in the details.

The Problem with 1.5°C: While the logic behind 1.5°C as a target is straightforward, making it easier for the general public to understand and relate to the concept of global warming, this simplicity has a major loophole that some oil companies and individuals with vested interests have exploited to spread misinformation. They have argued that global warming is a myth, claiming that we are actually experiencing a cooling trend.  

For instance, they point to recent cold snaps in Europe and severe winters in the Northeast as supposed evidence that global warming is a hoax. It is not only the media but also ordinary people like you and me who have been led to believe in this. Browsing through Twitter and YouTube, you can easily find comments and posts with similar claims that have garnered significant attention. The following example illustrates a misleading social media post claiming a need to "burn more fossil fuels", referencing recent frost advisories in Michigan and Wisconsin. Such posts often exploit isolated weather events to deny the broader trend of global warming, contributing to the spread of climate misinformation.

Twitter
Misleading social media post citing frost advisories in Michigan and Wisconsin to dispute global warming.

Twitter
The public perception on climate change is divided, illustrated by a tweet urging climate action contrasted with a dismissive response.

Average Temperatures

The average temperature of the world is a complex and fluctuating metric, varying slightly from year to year, and month to month within specific regions. The following graph from Berkeley Earth illustrates the trend. The red line indicates a significant warming trend, emphasizing the increasing global temperatures over time. The figure underscores the reality of global warming and the urgency to address climate change.

A graph showing the temperature of the earthDescription automatically generated
The graph depicts the global average temperature anomalies from 1850 to 2023, with data from Berkeley Earth and the UK Hadley Centre Source: Berkeley Earth.


It is important to note that the effects of temperature increase, and climate change are not distributed equally across the globe. The global south is experiencing significantly more warming and severe negative impacts compared to the global north. When you take the average, the situation appears less dire on paper, but the ground reality reveals a different picture.

While the trend of the average temperature is consistently increasing, this has not deterred climate change deniers. As the following example shows, they conveniently cherry-pick a small region spanning few years and claim that we are in a global cooling phase. 

Tweet claims global cooling based on selected temperature anomalies, suggesting CO2 warming is a hoax.

Even in the graph above, only 2022 is colder than 2015, while 2016, 2019, and 2020 are warmer. However, this aspect is often overlooked in such discussions.

They argue that there is no global warming, citing instances of extreme cold weather or claiming that CO2 is a plant food. These claims are misleading and divert attention away from meaningful change. They also ignore the fact that the climate is actually becoming more extreme due to the increased energy trapped in the atmosphere. 

In essence, winters are getting harsher, and summers are getting hotter. If you don't believe me, then look at the following graph. The figure displays the number of loss events from 1980 to 2019. The data indicates a notable increase in the frequency of these extreme events over the decades, with meteorological and hydrological events showing particularly significant growth. This trend suggests that extreme weather events have become more common, raising concerns about the impact of climate change on global weather patterns.

A graph of different colored columnsDescription automatically generated
Increase in Frequency of Extreme Weather Events (1980-2019). Source: Met Office.

And when we have a target of 1.5°C, it looks so distant into the future, it causes inaction. You know what could be even more devastating? If the world does reach 1.5°C, the media would likely kick off another trend with sensational headlines, like:  

“We've officially reached 1.5°C, what now?”

– which would only fuel climate doomerism and, ironically, lead to even greater inaction.

A Better Measure: PPM 

Imagine this scenario: You're leading a project in a country that aims to reduce CO2 emissions. When you crunch the numbers, you can proudly declare that you've reduced emissions by XYZ tons. This achievement would undoubtedly contribute to your carbon neutrality target. However, the question remains: how does this progress help humanity reach the 1.5°C target?

The truth is, we can't make a direct correlation between our actions and the 1.5°C goal because it's not quantifiable. Each country can individually work on Net Neutrality, but without an overarching goal that allows everyone to report with quantifiable results, achieving the target becomes significantly more challenging.

What alternative should we use as a reference point instead of 1.5°C? The answer lies in parts per million (PPM), which measures the amount of gas present in the atmosphere.  

  • In 1890, before the industrial revolution, the CO2 levels in the atmosphere were 295 PPM.  
  • By 1991, 100 years later, the CO2 levels had risen to 355 PPM, which is an increase of 60.  
  • In 2024, just 30 years later, we are now at 430 PPM, which is an increase of 75 (!!), and the levels only continue to rise. 

A 1 PPM reduction in atmospheric CO2 equates to 7.8 gigatons of CO2. To put this value into context, the USA as a whole emitted 6.3 Gigatons of CO2 in 2022 and collectively, we emit around 35 gigatons of it every year. Even during periods of reduced economic activity, like the recent COVID-19 pandemic when the whole world came to a standstill, the CO2 levels only had a marginal decrease. Now imagine the amount of innovation, funding, and action we must undertake to stay within 500 PPM. 

A Compromise: 1.5°C / 500 PPM 

I know what you're thinking; this PPM concept might be challenging for many people to grasp, which is why all countries agreed to use 1.5°C. However, if PPM is difficult for the average person to understand, a compromise could be to set a target of 1.5°C / 500 PPM of carbon. Because “temperature rise” is a result while CO2 is the reason.

Here's a comparison to make it clearer: Most of us typically set output goals, like “I want to lose 10kg”. However, action goals are much more specific, like "I will reduce my daily calorie intake by 100 calories until I reach 2000 kcal per day." Setting a 1.5°C target is similar to setting an output goal, while setting a target in PPM is more like an action goal.

This approach ensures that no one can distract us from the goal and makes it easier to combat misinformation. By focusing on both temperature and CO2 levels, we can better understand the complexities of climate change and work towards a more effective solution. The PPM target emphasizes the urgency and necessity of decarbonization more strongly than the 1.5°C target alone.

But will this method be implemented? We're not sure, but until next time...  

Follow the Sustainability Advocates' blog for more such nuanced dives into climate topics. Please send your feedback and any further questions regarding the topic via email to sdgadvocates@station.dk

** Note: The introduction story was enhanced for artistic purposes.  

The official English translation of the words of Mr. Laurent Fabius are: "To keep the median temperature increase well below 2 degrees Celsius and to make efforts to limit temperature rises to 1.5 C." 

Additional Reading

Highly recommended for those curious to learn more: explore how not only CO2 but also gases like methane and even water vapor contribute to global warming and learn whether we may have already surpassed the 500 PPM threshold.

Mitrevski, B., Etheridge, D., Derek, N., Fraser, P., Krummel, P., Steele, P., Langenfelds, R., Cleland, S., & Loh, Z. (2019, June 6). Why there’s more greenhouse gas in the atmosphere than you may have realised. The Conversation. http://theconversation.com/why-theres-more-greenhouse-gas-in-the-atmosphere-than-you-may-have-realised-118336

Methane and climate change – Global Methane Tracker 2022 – Analysis. (n.d.). IEA. Retrieved 19 June 2024, from https://www.iea.org/reports/global-methane-tracker-2022/methane-and-climate-change

Why do we blame climate change on carbon dioxide, when water vapor is a much more common greenhouse gas? | MIT Climate Portal. (n.d.). Retrieved 19 June 2024, from https://climate.mit.edu/ask-mit/why-do-we-blame-climate-change-carbon-dioxide-when-water-vapor-much-more-common-greenhouse

References

Almulhim, A. I., Alverio, G. N., Sharifi, A., Shaw, R., Huq, S., Mahmud, M. J., Ahmad, S., & Abubakar, I. R. (2024a). Climate-induced migration in the Global South: An in depth analysis. Npj Climate Action, 3(1), 1–12. https://doi.org/10.1038/s44168-024-00133-1

Cointe, B., & Guillemot, H. (2023). A history of the 1.5°C target. WIREs Climate Change, 14(3), e824. https://doi.org/10.1002/wcc.824

Explained: The 1.5 C climate benchmark | MIT Climate Portal. (n.d.). Retrieved 19 June 2024, from https://climate.mit.edu/posts/explained-15-c-climate-benchmark

Kuramochi, T., Höhne, N., Schaeffer, M., Cantzler, J., Hare, B., Deng, Y., Sterl, S., Hagemann, M., Rocha, M., Yanguas-Parra, P. A., Mir, G.-U.-R., Wong, L., El-Laboudy, T., Wouters, K., Deryng, D., & Blok, K. (2018). Ten key short-term sectoral benchmarks to limit warming to 1.5°C. Climate Policy, 18(3), 287–305. https://doi.org/10.1080/14693062.2017.1397495

Rohde, R. (2024, January 12). Global Temperature Report for 2023. Berkeley Earth. https://berkeleyearth.org/global-temperature-report-for-2023/

UN Climate Change (Director). (2015, December 16). Two Weeks of COP 21 in 10 Minutes. https://www.youtube.com/watch?v=gOgTxo_4Tgo