There is no doubt that man is affecting the environment. The greenhouse effect is easily demonstrable in the laboratory, and to deny man is heating the planet up is akin to denying Newton's laws of physics. And
there is no remaining doubt that the planet is warming up.
For a while, climate change deniers had an edge due to dropping temperatures in some areas, and the sea not being as much warmer as predicted.
As the sea covers 2/3 of the earth, it is a dominant factor in the analysis. However, even in the last 10 years, we now understand much more due to better satellite data on weather, and something called the ARGO buoy system (
http://www.argo.ucsd.edu/About_Argo.html ). Its data is available from NOAA (
https://www.ndbc.noaa.gov/) . It
originally measured only temperatures in the first 50 feet of the sea, and
it was assumed deeper waters were simply colder. But in trying to find the missing heat, new 'bouncing buoys' were deployed can now measure temperatures down to 3000 feet. And
the missing heat in the ocean was found, in large, static 'bubbles' under currents higher up, where the heat is trapped and does not reach the surface.
These currents also convey cold water from the poles, causing lower temperatures elsewhere from melting ice caps.
Incidentally, the increased heat reduces the amount of oxygen that can be retained, and the best study of the data so far, published in SCIENCE in 2018, finds that the lowest zone of the ocean, the 'dead zone,' has quadrupled in size since 1950 (
https://www.theguardian.com/environment/2018/jan/04/oceans-suffocating-dead-zones-oxygen-starved ). Other human factors besides the greenhouse effect, such as agricultural runoff, are adding to this (
https://earthsky.org/earth/dead-zone-gulf-of-mexico-2019 ), causing the dead zone to extend closer and closer to the surface. In combination with overfishing by modern 'super trawlers,' this has depleted large areas of the ocean of fish entirely.
The only remaining issue is whether our impact is significant compared to other factors affecting the global environment. Of these the most significant is heat from the sun, which slowly varies to some extent not predictable. On this there are obviously three alternatives.
- First, it is significant, in which something should be done.
- Second, it is not significant because other factors are making the temperature go up. In that case there is even more reason to do something about our own heat generation to extend our race's life.
- Third, other factors will bring about another mini ice age, in which case we will mostly go extinct. Our own heat would not be significant.
So given the choices, we should definitely do something, yes.