The IPCC's first of three reports on the Earth's climate: what does it say?

Since the Industrial Revolution, human activities have warmed the Earth’s atmosphere, oceans, and land. The two leading causes are burning fossil fuels and converting land from forests to agriculture. The Intergovernmental Panel on Climate Change (IPCC) consolidates all the peer-reviewed papers on the latest climate science to conclude about the state of the climate. The IPCC is currently in its sixth assessment cycle, producing the Sixth Assessment Report (AR6) with contributions by its three Working Groups. In this blog of our trilogy on IPCC, we focus on the first Working Group contribution, which addresses the latest physical understanding of the climate system and climate change.

The report of Working Group I consists of four parts: we will highlight the critical conclusions made per chapter, offering you an insight into climate risks and their potential impacts on your business.

The current State of the Climate

This first part of the report investigates the changes in greenhouse gas (GHG) emissions, weather patterns, and other physical measurements (like reductions in permafrost, Arctic sea ice, and other changing events on the Earth’s surface). The two most significant conclusions are:

  1. The rate of warming that has currently been observed is not seen in the last 400,000 years. Furthermore, the global sea level has risen faster since 1900 than any other preceding century over the previous 3000 years, which strongly supports the conclusion that the changing climate is mainly due to human activities;
  2. There is a widespread increase in observed hot extremes (leading to droughts) and heavy precipitation (leading to floods) for many regions of the world compared to 1950.
Possible Climate Futures

The second part looks at possible future climate scenarios that the climate could take depending on five different emission scenarios. All emissions scenarios can draw the following conclusions:

  1. Global temperature will keep rising until the middle of the century. The planet’s warming will only be limited to 1.5 degrees Celsius by 2100 if deep decarbonization takes place in the coming decades;
  2. Changes in the climate, such as increases in the frequency and intensity of hot extremes, marine heatwaves, and heavy precipitation, become more extensive in direct relation to global warming;
  3. As carbon emissions grow, ocean and land carbon sinks are projected to become less effective at slowing the accumulation of CO2 in the atmosphere.
  4. Many changes that occur due to past and future GHG emissions, such as melting ice sheets, global sea-level rise, and changes in the ocean, are irreversible for centuries to millennia.
Figure 1 - Global surface temperature change relative to 1850-1900

At the last climate summit, countries decided to commit to further reductions in greenhouse gas emissions to keep global temperature rise within 1.5°C. However, if the pledges made in Glasgow are kept, global warming will only be limited to 2.1°C (SPP2-4.5) by 2100. More action is needed to limit the temperature rise to 1.4°C by 2100.

Climate Information for Risk Assessment and Regional Adaptation

In this part, climate impact drivers (e.g., frost, aridity, mean wind speed, and sand and dust storms) are assessed, and their likelihood is presented based on future predictions. The key outcomes of this part are as follows:                                                                      

  1. Natural decadal variability will enhance or mask human-induced changes. However, it will have little effect on long-term global warming. This variability is important to consider in planning for the future, as it could lead to amplification or attenuation of the expected behaviour of climate impact drivers;
  2. Increased global warming will lead to increased and multiple changes in climate impact drivers, which will lead to more physical risks, arising from damage to property, infrastructure, and land; 
  3. The probability of low-likelihood, high-impact events (like abrupt ocean circulation changes) increases with limited coordination to reduce GHG emissions.
Limiting Future Climate Change

The final part of the report presents what limiting future climate change would require. The two key outcomes of this assessment are:

  1. Limiting human-induced climate change requires limiting cumulative GHG emissions, reaching at least net-zero emission, and rapid and sustained reductions in other GHG emissions (such as methane) by 2050 at the latest to have a good chance to remain within 1.5 degrees Celsius warming at the end of the century;
  2. Compared to high-emission scenarios, low-emission scenarios will, within years, lead to discernable differences in the concentration of greenhouse gas emissions and lead to improved air quality

In March and April, we will continue this IPCC series to dive into the Working Group II (Climate Adaptation) and III (Mitigation of Climate Change) contributions to climate adaptation and mitigation. In addition, we will identify climate risks and opportunities for companies in several industries, focusing mainly on the region of Western Europe.

Authors
Marc Latour

Marc Latour

Consultant, Sustainalize

Emile van Gelder

Emile van Gelder

Consultant, Sustainalize

Published on: 3 maart 2022

Share this article
Share on facebook
Share on twitter
Share on linkedin
Share on email

Other news in this category

Met OV

Phasellus dignissim nulla tincidunt ultrices interdum. Nulla a enim ullamcorper, consectetur ligula sit amet, rutrum ante. Praesent cursus viverra urna ut sagittis. Sed nunc felis, hendrerit sit amet odio a, mattis laoreet mi. Quisque diam turpis, convallis at ultrices eu, vehicula a urna. Suspendisse potenti.

Met OV

Phasellus dignissim nulla tincidunt ultrices interdum. Nulla a enim ullamcorper, consectetur ligula sit amet, rutrum ante. Praesent cursus viverra urna ut sagittis. Sed nunc felis, hendrerit sit amet odio a, mattis laoreet mi. Quisque diam turpis, convallis at ultrices eu, vehicula a urna. Suspendisse potenti.

Met OV

Phasellus dignissim nulla tincidunt ultrices interdum. Nulla a enim ullamcorper, consectetur ligula sit amet, rutrum ante. Praesent cursus viverra urna ut sagittis. Sed nunc felis, hendrerit sit amet odio a, mattis laoreet mi. Quisque diam turpis, convallis at ultrices eu, vehicula a urna. Suspendisse potenti.