Let us do that for you! As noted elsewhere, we say that Good Enough is 350 ppm and Too Bad is 500 ppm. Here is our reasoning:
What is really important is what the Earth's surface temperature is and there is plenty of evidence that this is related to atmospheric carbon dioxide levels. Before the Industrial Revolution began (early 19th century) the concentration of CO2 was around 280 ppm. When the first measurements took place at Mauna Loa in Hawaii in the 1950s, the global level was about 10% higher than that. It has risen steadily since then (see Figure 2 on the Climate In Context page). If present trends continue the global number will exceed 500 ppm halfway through this century. If we continue to do nothing to address rising CO2 levels we will exceed 2000 ppm in a couple of hundred years.
What does this mean for temperature? A good, and complicated question that you can study elsewhere. However, here are some of the things that might happen if we reach 500 ppm (and we almost certainly will):
A simulation of carbon dioxide transport in the atmosphere.
Credit: NASA/YouTube
page last edited February 6, 2018 by JHM