December 22, 2021

Extra: My Summary of the IPCC Climate Change Report 2021

This isn’t my usual post on this blog, but I was reflecting on the IPCC Climate Change Report for 2021 and decided to write a summary as extra credit for an oceanography class I’m taking. Here is the report I wrote:

Summary of IPCC Climate Change Report 2021

In this time of impending climate disaster, concepts in earth science are getting more attention than ever before. Billions of people watch, read, or listen to the news every day, and subjects in the earth science field have not been excluded from the millions of hours of live news and written articles. Earth science has five main branches: Geology, Meteorology, Climatology, Oceanography, and Environmental Science. These branches have played an extensive role in discovering the mysteries of the abiotic and biotic factors on Earth and the solar system. For example, geology is the study of geological features and processes. It has contributed to the understanding of the surface of the moon. Meteorology helps predict weather patterns or impending natural disasters. Oceanography is essential for understanding the oceans’ physical, chemical, and biological features. Environmental Science is key to understanding how life on Earth interacts with non-living things and how that affects Earth’s ecosystems. Finally, climatology is especially important in the modern era because of the climate crisis that is raising global temperatures and rising sea levels worldwide. This report will focus on the climatology branch of earth science by analyzing the IPCC climate report, “Climate Change 2021: The Physical Science Basis”. This topic belongs to this branch because this report surrounds the most recent climate crisis data and is a guide for policymakers to take action to prevent the climate crisis. This report will summarize the IPCC analysis of global climate change through 6 lenses: who, what, when, where, how, why. 

The 2021 IPCC report is the sixth assessment of global climate published by the IPCC and has caused widespread fear from environmentalists, politicians, national leaders, as well as ordinary citizens. It was written by the Intergovernmental Panel on Climate Change and edited by nineteen qualified scientists. The report covers the state of the global climate crisis. It proves that “It is unequivocal that human influence has warmed the atmosphere, ocean and land.” and that “Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred” (IPCC, 4). The article covers data collected over 2,000 years. This data shows trends in temperature, sea level, and extreme weather events. For example, the graph on page six of the report shows that the climate has warmed at an extremely alarming rate over the past 2,000 years. This trend is unprecedented and corresponds to the changes in the atmosphere caused by human influence. In addition, the report urges policymakers to proceed with extreme caution and immediately reduce CO2 emissions as fast as possible with the graphs titled: “Future emissions cause future additional warming, with total warming dominated by past and future CO₂ emissions.” The graphs show five possible trajectories of CO2 emissions over the next 100 years. The report shows that “Global surface temperature will continue to increase until at least mid-century under all emissions scenarios considered” (IPCC, 13). Scientists on the Intergovernmental Panel on Climate Change prove that human actions cause the climate crisis in this report. If no steps are taken to slow climate change, there will be disastrous consequences within the next 100 years and beyond. 

The IPCC report shows the analysis of where on Earth the effects of climate change are evident, how these effects appear, and why they appear. The report states that “Human-induced climate change is already affecting many weather and climate extremes in every region across the globe.” (IPCC, 8). This means that no country in the world is exempt from the consequences of greenhouse gas emissions. Every country in the world will feel the consequences of climate pollution, and most countries are already experiencing changes. For instance, “Evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and, in particular, their attribution to human influence, has strengthened” (IPCC, 8). These are just the effects already documented in the present day. Over time with higher global temperatures, the IPCC predicts that it will cause even more catastrophic natural disasters. The report also states that these effects were caused by the “Global surface temperature increase since 1850–1900 (OC) as a function of cumulative CO₂ emissions” (IPCC, 28). In the future, all the countries in the world must band together and agree to produce less greenhouse gas emissions for the sake of the future of humanity. In addition, the report states that “From a physical science perspective, limiting human-induced global warming to a specific level requires limiting cumulative CO2 emissions, reaching at least net zero CO2 emissions, along with strong reductions in other greenhouse gas emissions. Strong, rapid and sustained reductions in CH4 emissions would also limit the warming effect resulting from declining aerosol pollution and would improve air quality.” (IPCC, 27). The IPCC 2021 climate report, “Climate Change 2021,” proves that climate change is happening worldwide through climate extremes like cyclones, and they are happening primarily because of human-induced CO2 emissions.

The Intergovernmental Panel of Climate Change’s report, “Climate Change 2021: The Physical Science Basis,” proves the importance of the climate crisis through analysis of scientific data collected over 2,000 years. Written by hundreds of scientists and edited by nineteen, it covers the global climate crisis happening right now all around the world. It also discusses how the climate crisis presents its consequences and why they are happening. However, after reading this report, one question remains: what societal changes need to happen to force governments to take the climate crisis seriously? The UN Climate Change Conference also occurred this year, and it left many environmentalists feeling like nothing substantial got accomplished. This is a recurring pattern over the last few years since the climate crisis has gained public attention. The people of each nation want governmental action and have been protesting the lack of action taken regarding the subject. However, it seems as if each government is taking very few steps to create real change or is hesitant to believe the crisis exists. The report “builds upon the 2013 Working Group I contribution to the IPCC’s Fifth Assessment Report (AR5) and the 2018–2019 IPCC Special Reports of the AR6 cycle and incorporates subsequent new evidence from climate science” (IPCC, 4). If the IPCC has published six global climate change reports, and the last one was in 2019, it is shockingly disappointing that this did not get as much media and news attention in those years. We could have possibly been already on the road to decrease greenhouse gas emissions, so the worst possible outcome does not come to be a reality. Some countries have started their journey to lowering their carbon footprint. For example, many countries have now set net-zero emissions by mid-century with the UN’s Net Zero Coalition. In summary, the IPCC report on climate change is critical to the progression of human society on Earth. This report details the who, what, when, where, how, and why of the climate crisis. The future of the Earth and life as we know it depends on the actions we as collective humans take to reduce our greenhouse gas emissions in the next 100 years. We have the power to decide where we take our future: to the light or the grave. 



1. Natural Variability: Climatic fluctuations that occur without any human influence, such as volcanic eruptions, changes in solar activity and, on longer time scales, orbital effects and plate tectonics.

2. Evapotranspiration: The combined processes through which water is transferred to the atmosphere from open water and ice surfaces, bare soils and vegetation that make up the Earth’s surface.

3. Global Monsoon: The area in which the annual range of precipitation is greater than 2.5 mm day.

4. Compound Extreme Events: The combination of multiple drivers and/or hazards that contribute to societal or environmental risk.

5. Climatic Impact-Drivers (CIDs): Physical climate system conditions that affect an element of society or ecosystems. 

6. Carbon Budget: The maximum amount of cumulative net global anthropogenic CO2 emissions that would result in limiting global warming to a given level with a given probability, taking into account the effect of other anthropogenic climate forcers. 






IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. In Press.



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