Some of the consequences of global warming are here to stay, but achieving a healthy and livable planet is still possible with strong emissions reductions. How to do it?
The IPCC report: Climate Change 2021: The Physical Science Basis
During the 2015 United Nations Climate Change Conference (COP 21), the world leaders started negotiating the Paris Agreement, an international treaty on climate change mitigation, which entered into force on the fourth of November 2016. The treaty’s goal, described in its second article, is to limit the rise of the global average Temperature below two degrees Celsius above pre-industrial levels and to make efforts to hold the increase at one-point-five degrees Celsius above pre-industrial levels as means to reduce the risks and impacts of climate change. The first installment of the IPCC’s Sixth Assessment Report (AR6) has assessed our chances of surpassing those limits and delivered an up-to-date evaluation.
According to the report, limiting global warming to close to one-point-five degrees or even two degrees Celsius (three-point six degrees Fahrenheit) will become an unachievable goal without deep and rapid reductions in greenhouse gas emissions. Thanks to the progress in the scientific understanding of the global climate system’s response to anthropogenic greenhouse gas emissions and the bettered observational datasets to analyze historical warming, the report provided a future climate scenario based on an analysis of the current trajectory.
The Earth’s average temperature is likely to hit or exceed one-point-five degrees Celsius
Since 1850-1900, human-caused greenhouse gas emissions have been responsible for a warming of about one-point-one degrees Celsius. The report has concluded that averaged over the following two decades, the Earth’s average temperature is likely to hit or exceed one-point-five degrees Celsius of warming. On an industrial level, twenty-five corporate and state producing entities like Saudi Aramco and Gazprom are responsible for over half of the global industrial emissions emitted since 1988 (The Carbon Majors Database CDP Carbon Majors Report 2017). On a national level, twenty countries emit more than eighty percent of the total current greenhouse gas emissions (Earth System Science Data, 2019).
The intensification of the effects of climate change and the consequences
The impact of climate change differs among the various regions of the Earth, and the warming itself is twice as fast in the Arctic as the rest of the globe. The report shows that the effects of climate change will intensify in all regions in the following decades, as with further warming, there will be longer warm seasons with more frequent heatwaves and shorter cold seasons. Climate change is intensifying the water cycle and affecting rainfall patterns in various ways across different regions.
These changes are causing heavier rainfall, with the associated higher risk of flooding in multiple areas, and more frequent precipitations are expected to affect the areas in high latitudes. Other regions are likely to experience more intense droughts due to the intensification of the water cycle, and vast sections of the subtropics are projected to witness a decrease in precipitations.
Global warming will intensify permafrost thawing, the melting of the ice sheets and glaciers, and bring about the loss of seasonal snow cover and summer Arctic sea ice. The frequency of extreme sea events is expected to escalate due to the effects of climate change. Throughout the 21st century, coastal regions are projected to face increasing and severe coastal erosion and coastal flooding in low-lying areas due to the continuous sea-level rise.
Seas’s acidification
Between 1901 and 2018, the global mean sea level increased by 0.20 [0.15 to 0.25] m. Human activities are linked to the changes impacting the ocean, which occupies more than seventy percent of the globe’s surface (NOAA) and is home to ecosystems vital to the planet’s biodiversity.
The seas are experiencing reduced oxygen levels, acidification, warming, and more frequent marine heatwaves, affecting aquatic ecosystems and those who live in coastal areas. Around forty percent of the world’s population resides within 100 kilometers of the coast, and four of the world’s ten largest megacities (UN 2018) are located along coastlines. Fifty-six-point-two percent of the world’s population lives in cities (UN). Cities all over the world are projected to be affected by the consequences of climate change, such as rising temperatures and the flooding resulting from heavy precipitations.
Lampoon reporting: the advances in climate science worldwide in the last few years
«The IPCC report does not conduct new research itself. Instead, the hundreds of scientists who worked on this report came together to assess their current state of knowledge of the science of climate change, then reviewed over 14,000 studies, massive amounts of data. In this assessment, were welcomed new authors, as two-thirds of them had never been involved as the authors of previous IPCC reports. Our team was made up of scientists from sixty-six countries around the world», said the Chinese climatologist and co-chair of the Intergovernmental Panel on Climate Change Working group I, Panmao Zhai.
«Since the last assessment report in 2014, there have been advances in climate science worldwide. During these years, climate scientists filled in the gaps in observations of the past climate, improved climate models, and developed new ways to combine many types of evidence. As a result, today, we have the clearest picture of how the Earth’s climate functions and how human activity affects it. We know better than ever how the climate has changed in the past, how it is changing now, and how it will change in the future». Explained Valerie Masson-Delmotte, French climate scientist and co-chair of the Intergovernmental Panel on Climate Change Working group I.
IPCC report climate change forecast on the coming decades
«We have known for decades that the world is warming up. The recent changes we have seen in the climate are now widespread, rapid, and intensified. Some of the changes we see today, unprecedented in 1000s of years, have never been seen before. The recent rate of warming is unprecedented in at least 2000 years. To measure how the climate is changing, we have looked at a key indicator: the average Temperature of the Earth’s surface over at least a decade compared to the average in the late 1800s». Zhai said.
«Temperature is not the sole aspect that he has been altered. The levels of heat-trapping gases in the atmosphere are continuing to increase fast. Current CO2 concentrations are the highest they have been for at least 2 million years. Over the past 100 years, the sea level has risen at a faster rate than it ever did in at least 3000 years. The Arctic summer ice level is at its lowest in at least 1,000 years. The retreat of glaciers on a global scale since the 1950s is unprecedented in at least 2000 years. The warming we have experienced has far-reaching consequences. Climate change is contributing to an increase in extreme heat and droughts. Since the 1950s, hot extremes, including heat waves over land and marine heatwaves, have become more frequent and more intense. Heavy precipitations have become more frequent and more intense, and we see increasing drought in some regions. The consequences of heavy rainfall and droughts touch our whole planet, not just people, but also plants and animals, both nature and agriculture».
Limiting global warming to one-point-five degrees Celsius will be beyond reach
«There will be further warming in the coming decades. What is clear from this report is that unless there are immediate, strong, rapid, and large-scale reductions in greenhouse gas emissions, limiting global warming to one-point-five degrees Celsius will be beyond reach. The report shows that in the next twenty years, due to global warming, the average Temperature of the Earth’s surface is expected to reach or exceed one-point-five degrees Celsius above that of the late 1800s. If we rapidly reduce greenhouse gas emissions and if we reach global net-zero CO2 emissions around 2050, it is likely that we can keep global warming well below two degrees. If we do this, it is more likely than not that the temperature would decline in a gradual manner to below or around 1.5 degrees Celsius by the end of the century, with a transient overshoot of no more than zero-point-one degrees Celsius». Illustrated Masson-Delmotte.
The Intergovernmental Panel on Climate Change (IPCC report)
The UN body that assesses climate change-related science, has released The Working Group I Contribution to the Sixth Assessment Report (AR6), Climate Change 2021: The Physical Science Basis, on the ninth of August 2021. The Sixth Assessment Report (AR6) includes the contributions of three Working Groups. Working Group I focuses on the physical science basis, analyzing the physical science regarding the climate and its past, present, and future response to human activity. The contribution of Working Group II, which focuses on impacts, adaptation, and vulnerability, and that of Working Group III, which will be centered on mitigation, are scheduled for the approval plenaries in February and March 2022.
The Intergovernmental Panel on Climate Change (IPCC)
Established in 1988 by the World Meteorological Organization (WMO) and United Nations Environment Programme (UNEP). Its goal is to provide governments and policymakers with up-to-date scientific basis of climate change and its present and possible future impact offering them adaptation and mitigation strategies options. The previous IPCC report (AR5), authored by hundreds of leading scientists, was published in 2014. The latest Working group I report of 2021 reiterates the message of its predecessors.
It restates the anthropogenic nature of climate change, its impact on the natural world, and the immediate need to reduce greenhouse gas emissions (GHG). This report adds the updated physical understanding of the Earth’s climate system and climate change with multiple lines of evidence and the recent advances in climate science. Reductions in the emissions of greenhouse gases would limit climate change. Within a few years, in scenarios with low or very low greenhouse gas (GHG) emissions, there would be an impact on greenhouse gas and aerosol concentrations and an improvement of air quality.
