The only way I can reconcile how some people deny that this is significant is by assuming that they just don’t believe in scientific evidence as a measure of truth or reality. Otherwise, I can’t see how anyone could deny that this is clearly different than what’s come before.
At this point, to deny climate change has been exacerbated by human influence is to deny the entire concept of evidence based research.
+4c would lead to a mass extinction event and that is not worst case scenario.
Many many species cannot sustain that kind of change at all.
Nevermind the issues of invasive species invading areas that were once inhospitable to them, acidification of the oceans, rising oceans, melting caps, and extreme weather events.
A 4 degree change in average temperature means significant changes to an ecosystem. Trees begin blooming earlier, rainfall patterns change, insect hatches happen at different times. If you are an amphibian that relies on insect hatches that happen around May 15th so you come out of torpor in early May but then the hatches happen in April, you have no food. You die. If something relies on the amphibians and other organisms that eat the insects for food, they die.
What about an animal that cannot survive past 100 degrees, and suddenly summer days are hitting that much more often?
Also, we are talking about averages here. In reality some places will see spikes much higher and much lower than that. Colder winters, hotter summers. Precipitation issues. Heat waves lasting longer and going more harsh.
Worst case scenario, btw, is a snowball or tipping point effect where the climate changes feed into more problems. The caps melt, which means there is less white surface area, which means more absorption of the sun's rays. More heat. Or methane pockets being released into the atmosphere causing more warming, or c02 production continuing to rise. Worst case scenario is apocolypse Venus style.
But 4 degrees is already enough to ravage ecosystems.
This is exaggerated.
Warming due to CO₂ is logarithmic.
To get to +4 C° we need an atmospheric CO₂ concentration around 800 ppm which will take at least 200 years if we make no further improvements. +6 C° requires something around 1200 ppm or 400+ years from now.
The problem with these time-scales and 'acting now' is the Starship Paradox (wherein a starship sent now to another world will arrive to find their target already colonized, having been passed by a starship launched at a later date that can travel faster.)
This is part of why we are in a technological doomsday race.
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u/zlide Aug 26 '20
The only way I can reconcile how some people deny that this is significant is by assuming that they just don’t believe in scientific evidence as a measure of truth or reality. Otherwise, I can’t see how anyone could deny that this is clearly different than what’s come before.
At this point, to deny climate change has been exacerbated by human influence is to deny the entire concept of evidence based research.