The science behind global warming is complex.
The Earth is large, and its climate is influenced by numerous factors, many of which are not well understood. Additionally, numerous drivers of climate change are non-linear, meaning that a small change can produce very large changes to other factors, complicating estimations of the future.
Air pollution and greenhouse gases (GHGs) prevent heat from leaving Earth's atmosphere and therefore cause global warming we've been experiencing in recent decades. It's easy to imagine that by removing GHGs and reducing further emissions, the rising temperatures will stop, or even be reversed.
But that’s a bit like thinking that your lung cancer will go away if you stop smoking. Your health will certainly improve if you stop smoking, but treating the cancer requires other steps.
Reducing emissions, improving natural carbon sinks like forests, regenerative farming and even cleaning the air with machines will help reduce GHGs to sustainable levels, but these efforts will take decades to produce results. All the while, Earth’s temperatures will continue to rise, setting off self-reinforcing feedback loops, such as melting sea ice, that will further reduce Earth’s ability to reflect the warming sunlight, driving temperatures even higher.
The rising temperatures will cause crops to fail, bringing famine and mass emigration, destabilizing international politics and even leading to war. Sea levels will rise dramatically, putting many coastal populations underwater and creating further refugee crises. On top of that, numerous plant an animal species will continue to become extinct at an ever-increasing rate.
There are those who deny the time delay that GHG-reducing strategies involve. By referring to scientific models, some say that limiting or reducing GHGs has a rapid effect on reducing or limiting temperatures. Models are a favorite tool of scientists, but they do not take all of the data into account.
They aren’t even necessary to appreciate the problem: Earth’s energy imbalance―the difference between the amount of pent-up heat trying to escape the planet and the amount of that heat that is able to escape―indicates that average temperatures will still rise a full 1°C in the near-term no matter what happens to GHGs in the meantime. This is even after taking into account the temperature increase this imbalance has already caused. This makes focusing only on GHG reduction a fool's game.
Why does a small temperature increase matter?
With average temperatures in July of 20°C/68°F in Belfast, Ireland, Adam thinks it would be fine if temperatures were 21°C/69.8°F instead. A 1°C change in average temperatures implies a range of larger and smaller changes, periodically, at various places on the globe. So Adam in Belfast could also see temperatures in July of 33°C/91.4°F for a few days, for example. By the same token, peak July temperatures in Miami could move from their average of 28°C/82.5°F to a whopping 47°C/116.6°F for short periods! And all with "only" a 1°C change in average global temperatures.
Think about other life forms on Earth when we consider changing temperatures: People can withstand much higher temperature ranges than many life forms, which can be significantly harmed or even killed by changes to their ecosystems as small as only 1°C.