Consensus of scientists.
People (and that includes teachers) know they don’t have the time or capacity to learn about everything, and so frequently defer to the conclusions of experts.
Authors of seven climate consensus studies - imcluding Naomi Oreskes. Peter Doran, William Andreagg, Bart Verheggen, Ed Maibach, J. Stuart Carlton and John Cook co-authored a paper where the two key conclusions from the paper were:
1) Depending on exactly how you measure the expert consensus, it’s somewhere between 90% and 100% that agree humans are responsible for climate change, with most of the above studies finding 97% consensus among publishing climate scientists.
2) The greater the climate expertise among those surveyed, the higher the consensus on human-caused global warming.
The IPCC claims in its most recent report that it is '95 per cent' sure that 'more than half' of the warming 'since 1950' is man-made. It sounds impressive but it’s a pretty vague claim.
The
Special Report on Global Warming of 1.5 °C (
SR15) published by the IPCC on 8 October 2018 includes over 6,000 scientific references, and was prepared by 91 authors from 40 countries. What the report says is that human activities have already contributed 0.8–1.2 °C (1.4–2.2 °F) of warming above pre-industrial levels.
And you really cannot have much of a consensus about the future. Scientists are terrible at making forecasts, especially about complex systems. The climate is a chaotic system with multiple influences of which human emissions are just one.
And hence teachers will explain that any forecasts are from the IPCC. They will also explain what the IPCC is and how relevant reports are authored and what they are based on.
This is why the the IPCC actually gives a range of possible future temperatures. It thinks the world will be between about 1.5 and four degrees warmer on average by the end of the century. That’s a huge range, from marginally beneficial to terrifyingly harmful, so it is hardly a consensus of danger.
Did I say there was a "consensus of danger"?
What I said was:
"scientific consensus suggests that climate-warming trends over the past century are extremely likely due to human activities."
And school curriculums wil reflect exactly that.
What the latest report says is that:
"Climate models project robust differences in regional climate characteristics between present-day and global warming of 1.5°C, and between 1.5°C and 2°C. These differences include increases in: mean temperature in most land and ocean regions (high confidence), hot extremes in most inhabited regions (high confidence), heavy precipitation in several regions (medium confidence), and the probability of drought and precipitation deficits in some regions (medium confidence). By 2100, global mean sea level rise is projected to be around 0.1 metre lower with global warming of 1.5°C compared to 2°C (medium confidence). Sea level will continue to rise well beyond 2100 (high confidence), and the magnitude and rate of this rise depend on future emission pathways. A slower rate of sea level rise enables greater opportunities for adaptation in the human and ecological systems of small islands, low-lying coastal areas and deltas (medium confidence).
On land, impacts on biodiversity and ecosystems, including species loss and extinction, are projected to be lower at 1.5°C of global warming compared to 2°C. Limiting global warming to 1.5°C compared to 2°C is projected to lower the impacts on terrestrial, freshwater and coastal ecosystems and to retain more of their services to humans (high confidence).
Limiting global warming to 1.5°C compared to 2°C is projected to reduce increases in ocean temperature as well as associated increases in ocean acidity and decreases in ocean oxygen levels ( high confidence). Consequently, limiting global warming to 1.5°C is projected to reduce risks to marine biodiversity, fisheries, and ecosystems, and their functions and services to humans, as illustrated by recent changes to Arctic sea ice and warm-water coral reef ecosystems (high confidence).
Climate-related risks to health, livelihoods, food security, water supply, human security, and economic growth are projected to increase with global warming of 1.5°C and increase further with 2°C."
Then when you look into more detail about the assumptions of these projections the IPCC admits that the top of the range will only be reached if sensitivity to carbon dioxide is high, if world population growth re-accelerates, if carbon dioxide absorption by the oceans slows down, and if the world economy increases its coal use tenfold. Each of these assumptions are implausible so the extreme IPCC projection is very implausible. This is the skeptical middle ground.
School curriculums in various studies, ranging from Biology, to Environmental Science to Geography will be altered to again reflect these latest predictions, sourcing the relevant reports as described above.
Run this by one of your science teachers and tell me I'm wrong.
If they address climate modelling as part of their studies on climate change, students will examine various projections and make analysis of their plausibility, according to their discipline of their particular study.