Climate science: this is what the sixth IPCC report says
The IPCC has released the first part of their sixth report on climate science, which will be a cornerstone of this science in the near future. The report summarizes the basis of the physical science of climate change, bringing together over 14,000 studies submitted for review. Experts conclude that it is inevitable that we humans have excessively heated the planet, causing rapid changes to the oceans, ice and surface of the Earth.
The current state of many parts of the climate system has been unprecedented for many years. Many of these changes especially those affecting oceans, glaciers and global sea level, they are irreversible. Sudden changes and so-called tipping points are not to be underestimated.
Climate science, the IPCC publishes the sixth report on the matter
One of the key developments since the IPCC’s latest assessment report is strengthening links between man-made warming and increasingly severe weather conditions. This is now something certain. The consequences will continue to worsen with each level of warming, and there is no turning back for many of these consequences. It is expected that iglobal warming reaches 1.5 degrees Celsius by 2030 and if we fail to reduce levels of other greenhouse gases, the Earth will continue to warm.
Despite this bad news, experts are confident that reducing these large emissions can stabilize and reduce surface temperatures. The report uses the output of the latest generation of global climate models, produced as part of the sixth intercomparison of coupled models project. These coordinated efforts consist of “races” of about 100 distinct climate models produced by different groups of modelers around the world.
The model simulations themselves use a new set of scenarios, derived from shared socio-economic paths. They were initially developed to describe five broad narratives of future socio-economic development. They were used to develop scenarios of energy use, air pollution control, land use and greenhouse gas emissions developments, using integrated assessment models.
The report takes into account new and revised data e includes a reassessment of the metrics used to assess global warming. Also consider the recent occurrence of record warm years, noting that each year during 2015-20 was likely warmer than any previous year. The current state, 2021 also promises to be among the seven hottest years on record.
How warmer will the Earth be in the future?
This is largely due to the dataset innovations that have taken place over the past eight years, which take greater account of historical changes in the way sea temperatures are measured and provide more comprehensive global coverage. The report also includes an analysis of the difference between key global warming metrics. It is based on a combination of ground-surface air temperatures from weather stations and the sea surface temperaturemeasured using buoys and ships.
It differs slightly from the global surface air temperature, which is generally used by climate models. GSAT is also based on air temperatures at the earth’s surface, but these are combined with air temperatures above seawater. Although closely related, these two measures are distinct from each other.
As for the greenhouse gases that cause global warming, the report states that CO2, methane and nitrous oxide concentrations have increased at unprecedented rates on centennial time scales at least in the last 800,000 years. These concentrations are higher than those of 2 million years. It is virtually certain that global surface temperature increases and associated changes can be limited through rapid and substantial reductions in global GHG emissions.
The global surface temperature will continue to increase until at least the middle of the century in all the emissions scenarios considered. Global warming of 1.5 ° C and 2 ° C will be overcome during the 21st century unless it is see profound reductions in CO2 and other greenhouse gas emissions in the coming decades.
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