Ozone layer in Recovery, Montreal Protocol reducing Greenhouse gases set to avoid global warming by about 0.5–1°C by 2050

Photo: IISD/ENB OEWG contact group meeting

The Montreal Protocol, the little international treaty that reduces ozone depleting substances but also assists greatly with reducing greenhouse gases causing global warming.

The 45th Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol met in Thailand between 2 to 7 July 2023.

The IISD/ENB summary report of the meeting notes:

"The success of the Montreal Protocol was again highlighted and further specified by the Scientific Assessment Panel (SAP): stratospheric ozone is on the way to full recovery, expected by around 2040 for the near-global average, around 2045 in the Arctic, and around 2066 in the Antarctic. At the same time, the decline in ozone depleting substance (ODS) emissions due to compliance with the Protocol is set to avoid global warming by about 0.5–1°C by 2050, compared to an uncontrolled increase in ODS. Another 0.3–0.5°C of avoided warming by 2100 is estimated due to the phase-down of HFCs, the ozone-friendly but climate-warming greenhouse gases controlled under the Kigali Amendment to the Montreal Protocol."

Atmosphere of Hope: Tim Flannery and Clive Hamilton on #climate engineering at #MWF15

This article was originally published at nofibs.com.au

Professors Clive Hamilton and Tim Flannery on the morality, necessity and possibilities of engineering the climate by carbon dioxide removal (CDR) technologies. A Melbourne Writers Festival event, Saturday 29 August 2015.

I attended the discussion between Professors Clive Hamilton and Tim Flannery at the Melbourne Writers workshop on Saturday morning. Climate change has been a prominent theme of this year's festival, and I have attended a few sessions examining climate stories, sense of place, and importance of communication and narrative.

Climate Geo-engineering study on sulphate injection shows Hydrological disruption to rain and severe drought

While politicians have effectively dithered on robust action to reduce greenhouse gas emissions over the last 20 years we are hearing more about geo-engineering proposals to moderate rising temperatures. But the latest study from the University of Reading scientists modelling solar radiation management, and in particular atmospheric aerosol injection - one of the easiest geo-engineering proposals to do at large scale - says such a project would result in a major decrease in tropical rainfall and an increase in drought in many regional areas.

The Reading University study concentrated on the consequences on geo-engineering methods to change the solar radiation reaching the earth: through mirrors above the atmosphere; and injecting sulfate aerosols into the atmosphere to reflect solar radiation. The first could prove hideously expensive and is at the moment impractical, but the second method is quite achieveable at reasonable cost.

The study - Weakened tropical circulation and reduced precipitation in response to geoengineering (Full paper) - looks at aerosol injection in particular and the projected impacts. It was published in Environmental Research Letters.

Related: Yale Environment360: Solar Geoengineering: Weighing Costs of Blocking the Sun’s Rays (9 Jan 2014)

Engineering Professor: Install solar panels to combat Global Warming rather than paint roofs white

A Stanfoord University Professor of civil and environmental engineering has suggested that installing solar photo-voltaic panels on your house would be a better contribution to reducing global temperatures than the geo-engineering solution of painting vast numbers of urban roofs white to combat the urban heat island contribution to global warming. "There does not seem to be a benefit from investing in white roofs," said Professor Jacobson. "The most important thing is to reduce emissions of the pollutants that contribute to global warming."

Cities and urban areas release more heat to the atmosphere than rural areas - this is known as the Urban Heat Island effect. Climate skeptics have used this to argue that surface temperature data is contaminated by the location of data collection in urban areas. A new scientific study by Stanford University researchers has quantified the contribution of the heat islands on a global basis for the first time, showing that the contribution to global warming from urban heat islands is modest compared with what greenhouse gas emissions contribute.

Related: Skeptical Science: Does Urban Heat Island effect exaggerate global warming trends? | RealClimate: The Surface Temperature Record and the Urban Heat Island