IPCC Presents Special Report on Limiting Global Warming to 1.5°C

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‘Next few years are probably the most important in human history…’

 Incheon, Republic of Korea, October 8, 2018: Limiting global warming to 1.5°C compared to 2°C could go hand in hand with ensuring a more sustainable and equitable society, the Intergovernmental Panel on Climate Change (IPCC) said on October 8 in a  ‘Special Report’.

The report will be the key scientific input into the coming Katowice Climate Change Conference in Poland in December 2018, when governments review the Paris Agreement to tackle climate change. Nevertheless, limiting global warming to 1.5°C would require rapid, far-reaching and unprecedented changes in all aspects of society with clear benefits to people and natural ecosystems, the IPCC said in a new assessment.

“With more than 6,000 scientific references cited and the dedicated contribution of thousands of expert and government reviewers worldwide, this important report testifies to the breadth and policy relevance of the IPCC,” said Hoesung Lee, Chair of the IPCC. Ninety-one authors and review editors from 40 countries prepared the IPCC report in response to an invitation from the United Nations Framework Convention on Climate Change (UNFCCC) when it adopted the Paris Agreement in 2015.

“We are already seeing the consequences of 1°C of global warming through more extreme weather..”

“One of the key messages that comes out very strongly from this report is that we are already seeing the consequences of 1°C of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice, among other changes,” said Panmao Zhai, Co-Chair of IPCC Working Group I.

The report highlights a number of climate change impacts that could be avoided by limiting global warming to 1.5°C compared to 2°C, or more. For instance, by 2100, global sea level rise would be 10 cm lower with global warming of 1.5°C compared with 2°C. The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5°C, compared with at least once per decade with 2°C. Coral reefs would decline by 70-90 percent with global warming of 1.5°C, whereas virtually all (> 99 percent) would be lost with 2°C.

“Every extra bit of warming matters, especially since warming of 1.5°C or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems,” said Hans-Otto Pörtner, Co-Chair of IPCC Working Group II.

Limiting global warming would also give people and ecosystems more room to adapt and remain below relevant risk thresholds, added Pörtner. The report also examines pathways available to limit warming to 1.5°C, what it would take to achieve them and what the consequences could be. “The good news is that some of the kinds of actions that would be needed to limit global warming to 1.5°C are already underway around the world, but they would need to accelerate,” said Valerie Masson-Delmotte, Co-Chair of Working Group I.

 

Rapid transitions including the  transport sector required

The report finds that limiting global warming to 1.5°C would require “rapid and far-reaching” transitions in land, energy, industry, buildings, transport, and cities. Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050. This means that any remaining emissions would need to be balanced by removing CO2 from the air.

“Limiting warming to 1.5°C is possible within the laws of chemistry and physics but doing so would require unprecedented changes,” said Jim Skea, Co-Chair of IPCC Working Group III.

The decisions we make today are critical in ensuring a safe and sustainable world for everyone, both now and in the future, said Debra Roberts, Co-Chair of IPCC Working Group II.  “This report gives policymakers and practitioners the information they need to make decisions that tackle climate change while considering local context and people’s needs. The next few years are probably the most important in our history,” she said.

The IPCC is the leading world body for assessing the science related to climate change, its impacts and potential future risks, and possible response options. The report was prepared under the scientific leadership of all three IPCC working groups. Working Group I assesses the physical science basis of climate change; Working Group II addresses impacts, adaptation and vulnerability; and Working Group III deals with the mitigation of climate change.

The Paris Agreement adopted by 195 nations at the 21st Conference of the Parties to the UNFCCC in December 2015 included the aim of strengthening the global response to the threat of climate change by “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels.”

The report’s full name is ‘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’.
For more information, including links to the IPCC reports, go to: www.ipcc.ch

Source: IPCC

Rising Seas Slowed by Increasing Water on Land

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NASA, University Study Shows Rising Seas Slowed by Increasing Water on Land

Results will lead to a refinement of global sea level budgets

Washington, D.C., February 11,2016: New measurements from a NASA satellite have allowed researchers to identify and quantify, for the first time, how climate-driven increases of liquid water storage on land have affected the rate of sea level rise.

A new study by scientists at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, and the University of California, Irvine, shows that while ice sheets and glaciers continue to melt, changes in weather and climate over the past decade have caused Earth’s continents to soak up and store an extra 3.2 trillion tons of water in soils, lakes and underground aquifers, temporarily slowing the rate of sea level rise by about 20 percent.

The water gains over land were spread globally, but taken together they equal the volume of Lake Huron, the world’s seventh largest lake. The study is published in the Feb. 12 issue of the journal Science.

Each year, a large amount of water evaporates from the oceans, falls over land as rain or snow, and returns to the oceans through runoff and river flows. This is known as the global hydrologic, or water, cycle. Scientists have long known small changes in the hydrologic cycle — by persistent regional changes in soil moisture or lake levels, for instance — could change the rate of sea level rise from what we would expect based on ice sheet and glacier melt rates. However, they did not know how large the land storage effect would be  because there were no instruments that could accurately measure global changes in liquid water on land.

“We always assumed that people’s increased reliance on groundwater for irrigation and consumption was resulting in a net transfer of water from the land to the ocean,” said lead author J.T. Reager of JPL, who began work on the study as a graduate student at UC Irvine. “What we didn’t realize until now is that over the past decade, changes in the global water cycle more than offset the losses that occurred from groundwater pumping, causing the land to act like a sponge — at least temporarily. These new data are vital for understanding decadal variations in sea level change. The information will be a critical complement to future long-term projections of sea level rise, which depend on melting ice and warming oceans.”

The 2002 launch of NASA’s Gravity Recovery and Climate Experiment (GRACE) twin satellites provided the first tool capable of quantifying land liquid water storage trends. By measuring the distance between the two GRACE satellites to within the width of a strand of human hair as they orbit Earth, researchers can detect changes in Earth’s gravitational pull that result from regional changes in the amount of water across Earth’s surface. With careful analysis of these data, JPL scientists were able to measure the change in liquid water storage on the continents, as well as the changes in ice sheets and glaciers.

“These results will lead to a refinement of global sea level budgets, such as those presented in the Intergovernmental Panel on Climate Change (IPCC) reports, which acknowledge the importance of climate-driven changes in hydrology, but have been unable to include any reliable estimate of their contribution to sea level changes,” said JPL senior water scientist Jay Famiglietti, senior author of the paper and a professor at the University of California, Irvine.

Famiglietti also noted the study is the first to observe global patterns of changes in land water storage, with wet regions getting more wet and dry areas getting drier.

“These patterns are consistent with earlier observations of changing precipitation over both land and oceans, and with IPCC projections of changing precipitation under a warming climate,” he said. “But we’ll need a much longer data record to fully understand the underlying cause of the patterns and whether they will persist.”

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing. For more on NASA’s sea level rise research please visit: https://sealevel.nasa.gov/

Source: NASA