This is NOT easy stuff to understand. But people should know this report was done (it's the continuation of work from the Paris Climate Change Agreement, agreed on by basically most every country except Trumpia. (This Mother Jones article gives more nuance)
It looks like the Press Release is the most understandable part of the report, and it's still work to get through. Here's some key excerpts.
“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.
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 2oC.
“Every extra bit of warming matters, especially since warming of 1.5oC 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 1.5oC, what it would take to achieve them and what the consequences could be.
From what I can tell, the report is basically is comparing what will happen under the goals of limiting global temperature rise to 1.5˚C or to 2.5˚C, the feasibility of both these goals, and the impacts on the earth and life for each.
I tried to skim the main headings of the summary of findings, but they are pretty dense reading, so I've picked the list of terms listed at the end. If people learn these terms, that would be a good start. Then they look at the parts of the report.
Box SPM 1: Core Concepts Central to this Special Report
Global mean surface temperature (GMST): Estimated global average of near-surface air temperatures over land and sea-ice, and sea surface temperatures over ice-free ocean regions, with changes normally expressed as departures from a value over a specified reference period.
When estimating changes in GMST, near-surface air temperature over both land and oceans are also used.19{1.2.1.1}
Pre-industrial: The multi-century period prior to the onset of large-scale industrial activity around 1750. The reference period 1850–1900 is used to approximate pre-industrial GMST. {1.2.1.2}
Global warming: The estimated increase in GMST averaged over a 30-year period, or the 30-year period centered on a particular year or decade, expressed relative to pre-industrial levels unless otherwise specified. For 30-year periods that span past and future years, the current multi-decadal warming trend is assumed to continue. {1.2.1}
Net zero CO2 emissions: Net-zero carbon dioxide (CO2) emissions are achieved when anthropogenic CO2 emissions are balanced globally by anthropogenic CO2 removals over a specified period.
Carbon dioxide removal (CDR): Anthropogenic activities removing CO2 from the atmosphere and durably storing it in geological, terrestrial, or ocean reservoirs, or in products. It includes existing and potential anthropogenic enhancement of biological or geochemical sinks and direct air capture and storage, but excludes natural CO2 uptake not directly caused by human activities.
Total carbon budget: Estimated cumulative net global anthropogenic CO2 emissions from the preindustrial period to the time that anthropogenic CO2 emissions reach net zero that would result, at some probability, in limiting global warming to a given level, accounting for the impact of other anthropogenic emissions. {2.2.2}
Remaining carbon budget: Estimated cumulative net global anthropogenic CO2 emissions from a given start date to the time that anthropogenic CO2 emissions reach net zero that would result, at some probability, in limiting global warming to a given level, accounting for the impact of other anthropogenic emissions. {2.2.2}
Temperature overshoot: The temporary exceedance of a specified level of global warming.
Emission pathways: In this Summary for Policymakers, the modelled trajectories of global anthropogenic emissions over the 21st century are termed emission pathways. Emission pathways are classified by their temperature trajectory over the 21st century: pathways giving at least 50% probability based on current knowledge of limiting global warming to below 1.5°C are classified as ‘no overshoot’; those limiting warming to below 1.6°C and returning to 1.5°C by 2100 are classified as ‘1.5°C limited-overshoot’; while those exceeding 1.6°C but still returning to 1.5°C by 2100 are classified as ‘higher-overshoot’.
Global mean surface temperature (GMST): Estimated global average of near-surface air temperatures over land and sea-ice, and sea surface temperatures over ice-free ocean regions, with changes normally expressed as departures from a value over a specified reference period.
When estimating changes in GMST, near-surface air temperature over both land and oceans are also used.19{1.2.1.1}
Pre-industrial: The multi-century period prior to the onset of large-scale industrial activity around 1750. The reference period 1850–1900 is used to approximate pre-industrial GMST. {1.2.1.2}
Global warming: The estimated increase in GMST averaged over a 30-year period, or the 30-year period centered on a particular year or decade, expressed relative to pre-industrial levels unless otherwise specified. For 30-year periods that span past and future years, the current multi-decadal warming trend is assumed to continue. {1.2.1}
Net zero CO2 emissions: Net-zero carbon dioxide (CO2) emissions are achieved when anthropogenic CO2 emissions are balanced globally by anthropogenic CO2 removals over a specified period.
Carbon dioxide removal (CDR): Anthropogenic activities removing CO2 from the atmosphere and durably storing it in geological, terrestrial, or ocean reservoirs, or in products. It includes existing and potential anthropogenic enhancement of biological or geochemical sinks and direct air capture and storage, but excludes natural CO2 uptake not directly caused by human activities.
Total carbon budget: Estimated cumulative net global anthropogenic CO2 emissions from the preindustrial period to the time that anthropogenic CO2 emissions reach net zero that would result, at some probability, in limiting global warming to a given level, accounting for the impact of other anthropogenic emissions. {2.2.2}
Remaining carbon budget: Estimated cumulative net global anthropogenic CO2 emissions from a given start date to the time that anthropogenic CO2 emissions reach net zero that would result, at some probability, in limiting global warming to a given level, accounting for the impact of other anthropogenic emissions. {2.2.2}
Temperature overshoot: The temporary exceedance of a specified level of global warming.
Emission pathways: In this Summary for Policymakers, the modelled trajectories of global anthropogenic emissions over the 21st century are termed emission pathways. Emission pathways are classified by their temperature trajectory over the 21st century: pathways giving at least 50% probability based on current knowledge of limiting global warming to below 1.5°C are classified as ‘no overshoot’; those limiting warming to below 1.6°C and returning to 1.5°C by 2100 are classified as ‘1.5°C limited-overshoot’; while those exceeding 1.6°C but still returning to 1.5°C by 2100 are classified as ‘higher-overshoot’.
Impacts: Effects of climate change on human and natural systems. Impacts can have beneficial or adverse outcomes for livelihoods, health and well-being, ecosystems and species, services, infrastructure, and economic, social and cultural assets.
Risk: The potential for adverse consequences from a climate-related hazard for human and
natural systems, resulting from the interactions between the hazard and the vulnerability and exposure of the affected system. Risk integrates the likelihood of exposure to a hazard and the magnitude of its impact. Risk also can describe the potential for adverse consequences of adaptation or mitigation responses to climate change.
Climate-resilient development pathways (CRDPs): Trajectories that strengthen sustainable development at multiple scales and efforts to eradicate poverty through equitable societal and systems transitions and transformations while reducing the threat of climate change through ambitious mitigation, adaptation, and climate resilience.
Risk: The potential for adverse consequences from a climate-related hazard for human and
natural systems, resulting from the interactions between the hazard and the vulnerability and exposure of the affected system. Risk integrates the likelihood of exposure to a hazard and the magnitude of its impact. Risk also can describe the potential for adverse consequences of adaptation or mitigation responses to climate change.
Climate-resilient development pathways (CRDPs): Trajectories that strengthen sustainable development at multiple scales and efforts to eradicate poverty through equitable societal and systems transitions and transformations while reducing the threat of climate change through ambitious mitigation, adaptation, and climate resilience.
Steve, thanks for posting this and will try to dig in a bit. Gene and I are taking this on board very seriously as we design our final home here (Isle of Wight) so it's Net Zero carbon, (near) passivhaus and will filter air. It does cost more (at present) but we really couldn't build not doing this. Trouble with giving a damn, I guess!
ReplyDeleteWe all CAN do our bit, some more than others, as we don't own a car, have greatly reduced meat consumption, taking up gardening, wearing charity shop clothes quite a bit, recycling, reducing, it adds up. We're also asking our MPs to act on regulating use of plastics in commercial vending, shopping and such.
We might not save the world from what we've all done, but more of us can give it a go.
Oh, and something folks can look into. In Britain, there are energy suppliers which invest in non-carbon based energy and supply and buy from the national grid based on these filters -- the energy we buy costs a bit more, but it helps change the grid energy supply as more customers buy from these kind of suppliers. It's all business model and such and it works -- production of cleaner energy is going up, and that's incredibly important.
DeleteGreat! Thanks.
DeleteDire news. One more reason to get rid of Trump and his climate denying cronies -- like the new appointee. Jeez.
ReplyDelete