Pro: The Warming Isn’t Evenly Dispersed
Global warming reaching 1.5 degrees doesn’t mean that average temperatures in some places won’t rise significantly beyond that number. Again – it’s just the global average.
Then there’s the fact that as average temperatures rise, spikes and heatwaves will go much, much higher than just 1.5 degrees.
As the Intergovernmental Panel on Climate Change (IPCC) – basically the gold standard for climate science – reported: “Several regional changes in climate are assessed to occur with global warming up to 1.5°C compared to pre- industrial levels, including warming of extreme temperatures in many regions.”
That’s rock-star-scientist-speak for: “If global warming reaches up to 1.5 degrees, the hottest of the hot temperatures will increase and many (more) places will get dangerously hot.”Source:https://www.climaterealityproject.org/blog/why-15-degrees-danger-line-global-warming
Two degrees, says Johan Rockström, director of the Stockholm Resilience Center, “contains significant risks for societies everywhere; 1.5 looks much more scientifically justifiable.”
Ecosystems would feel the difference too. Take tropical coral reefs, which already regularly come under stress because of high ocean temperatures, suffering “bleaching” especially during El Nino events — as happened on the Great Barrier Reef in Australia this year. Most can now recover when the waters cool again, but today’s exceptional temperature may soon become the new normal. “Virtually all tropical coral reefs are projected to be at risk of severe degradation due to temperature-induced bleaching from 2050 onwards,” as warming slips past 1.5 degrees, reports Schleussner.
By some estimates, curbing warming at 1.5 degrees could be sufficient to prevent the formation of an ice-free Arctic in summer, to save the Amazon rainforest, and to prevent the Siberian tundra from melting and releasing planet-warming methane from its frozen depths. It could also save many coastal regions and islands from permanent inundation by rising sea levels, particularly in the longer run.
In 2100, the difference in sea level rise between 1.5 and 2 degrees would be relatively small: 40 centimeters versus 50 centimeters. But centuries later, as the impact of warmer air temperatures on the long-term stability of the great ice sheets of Greenland and Antarctica takes hold, it would be far greater.Source: https://e360.yale.edu/features/what_would_a_global_warming_increase_15_degree_be_like
Con: These Temperatures Are Not Abnormal or Dangerous
Climate alarmists (and the IPCC) say we need to limit global warming to 1.5°C above pre-industrial times to avoid disastrous consequences, but data show we have already reached such temperatures. European temperature data show temperatures began rising about the year 1890. The U.N. Intergovernmental Panel on Climate Change (IPCC), says:
Why is it necessary and even vital to maintain the global temperature increase below 1.5°C versus higher levels? Adaptation will be less difficult. Our world will suffer less negative impacts on intensity and frequency of extreme events, on resources, ecosystems, biodiversity, food security, cities, tourism, and carbon removal.
Note that this was before the large modern rise in CO2 emissions, and as shown by the IPCC, catastrophic predictions of extreme climate change have not come true.
Climate alarmists warn we must take drastic steps within the next 10 years to keep warming to 1.5°C above pre-industrial conditions. They claim that warming beyond that threshold will unleash a crisis of substantially worse extreme weather events and other climate harms. However, Europe possesses the best, longest-running temperature records on the planet, and those temperature records show warming has already exceeded 1.5°C. Nevertheless, alarmists’ catastrophic predictions are not coming true.
Below in Figure 1 is the Berkeley Earth average surface temperature record for Europe. Europe is a good location to analyze, because some of the longest continuous temperature records are from Europe. It shows a warming of 1.5°C has already occurred there. In fact the rise is even greater, at 2.0°C since about 1820. Yet catastrophic weather events such as long-duration heat waves have not occurred. So where are the predicted climate catastrophes?
No cities gone underwater. No increase in heat waves or cold waves. No islands sinking into the ocean. No increase in hurricanes. No millions of climate refugees. The tragedies being pushed by activists and politicians for the last 30 years simply haven’t come to pass.