An Overview of the IPCC Special Report on 1.5 Degrees of Warming (Part 1)

Today is Earth Day, which was established on April 22, 1970 when millions of people took to the streets to protest the negative impacts of 150 years of industrial development. Fast forward to 2019, Earth Day is now a global event filled with political action and civic participation.

Along the lines of recognizing the impacts from industrial development, and specifically impacts to our climate, our two-part blog series focuses on a special report released by the Intergovernmental Panel on Climate Change (IPCC). The blog series is written by Maggie Zeh, senior at Rock Canyon High School; Part 1 provides a summary and highlights of the report. Maggie worked with Lotus as part of her senior career exploration coursework. She is passionate about the environment and interested in pursuing a career in sustainability. Maggie plans to continue following these passions this fall as she starts studying at the University of Michigan, where she will major in Environmental Science.

An Overview of the IPCC Special Report on 1.5 Degrees of Warming

Photo by Diana Parkhouse on Unsplash

Photo by Diana Parkhouse on Unsplash

In October 2018, the Intergovernmental Panel on Climate Change (IPCC) released a special report outlining the impacts of climate change if temperatures raise 1.5 ºC above pre-industrial levels. This report also analyzes the difference between limiting climate change to 1.5 ºC as opposed to 2 ºC. The goal of this report is to explain how the response to climate change, sustainable development, and the eradication of poverty can be most effectively addressed and expanded. The data and projections in this report are based on scientific data in addition to socioeconomic influences.

 Understanding Global Warming of 1.5 ºC

               Human actions have already caused global temperatures to rise by about 1 ºC. This number will most likely rise to 1.5 ºC between 2030 and 2052 due to human impact if conditions remain the same. This means anthropogenic global warming (i.e., the climate change caused solely by human activity) is approximately 0.2 ºC per decade. This increase in temperature will be accompanied by heightened risks as climate change escalates. Changes in natural systems have already been observed and are expected to be more drastic as temperatures continue to rise. Mitigation actions can help reduce climate related risks in the future. In order to prevent further warming and reverse some damages, negative net anthropogenic CO2 emissions may be required. Negative net emissions can be achieved through projects including carbon capture, storage, and sequestration. These actions remove CO2 from the atmosphere, which results in reductions to total global CO2 levels. More challenges will be experienced at a warming of 2 ºC as opposed to 1.5 ºC. Various ecosystems have already started to experience negative effects of climate change, some of which are most likely irreversible. With increased mitigation and adaptation efforts, these risks can be reduced.

 Potential Impacts and Risks of Climate Change

                       Some of the most widely experienced impacts of climate change above 1.5 ºC include increases in average and extreme temperatures in many inhabited regions and altered precipitation levels. Most regions will experience a greater number of hot days, and this will become increasingly more extreme closer to the equator. Changes in precipitation will cause more droughts in some regions while it will produce more tropical cyclones and floods in others. Sea levels are expected to rise nearly a meter by 2100 at current rates. This can also cause irreversible loss of ice sheets in Antarctica and Greenland, which would consequently cause sea levels to rise multiple meters further after the year 2100. Small islands and costal areas with low elevations will have to adapt the most to this change in sea level. A great loss of biodiversity and various ecosystems can also be an expected result of climate change. Forest fires and the spread of invasive species is expected to increase along with climate change. Limiting global warming to 1.5 ºC as opposed to 2 ºC will likely reduce the increase in ocean temperatures and acidification and limit a decrease in ocean oxygen levels. The habitats of many marine animals will most likely shift further North or South, damaging many ecosystems. At 1.5 ºC, only 10%-30% of coral reefs are expected to persist. More adaptation measures will need to be taken if temperatures raise to 2 ºC and it will be easier to adapt at 1.5 ºC.

In addition to causing damage to the natural world, climate change can also pose risks to many socio-economic concerns. This can include food and water security, health issues, livelihood, human security, and economic growth. Climate change will pose the greatest risks to regions in the Arctic, dry land, and small islands as well as Least Developed Countries (countries with the least socioeconomic development). Poverty and disadvantage are also expected to rise as a result of climate change. Human health will likely experience negative consequences as well. If global temperatures raise to 2 ºC, more crop yields will be reduced by a greater amount than they would be at 1.5 ºC. Deaths related to heat and the ozone are expected to increase, as well as vector born diseases. There are limits to all regions’ abilities to adapt, and they are higher at 2 ºC.


The first half of this blog outlines the findings from the IPCC Special Assessment Report regarding what has caused climate change and the impact it will have on different aspects of the natural and human worlds. Human activity has played a key role in this issue and will most likely be one of the most effected factors. At current emissions rates, a variety of risks will be presented to the world, so mitigation and adaptation are both necessities. Factors like geographical region and socioeconomic development will determine the extent to which populations and natural systems will be impacted.

Multiple pathways have been created which outline different measures that can be taken to address the issue of climate change, and what their effect will be. Some of these pathways are in fact able to prevent climate change from reaching 2 ºC, which is ideal. Part two of this blog will highlight some of these opportunities which will reduce the risks experienced by humans and natural systems.


IPCC, 2018: Summary for Policymakers. In:Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty[Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, Maycock, M. Tignor, and T. Waterfield (eds.)].World Meteorological Organization, Geneva, Switzerland, 32 pp.