The latest U.N. forecast should remind us that the climate is an immensely complex system.

The report released before last year’s climate conference points to global warming of between two and three degrees centigrade over pre-industrial levels, considerably less than the increase of four or even five degrees that was once widely forecast.

We cannot pretend to be certain what it will look like at the end of the century, or how much of any change will be due to human activity, or what the effects of climate change will be. We do know that climate modeling can give some indications as to what may lie ahead, but we also know that the models are by no means infallible (indeed, some argue that they are profoundly flawed). Those who forecast what the climate will do and why (and those who interpret those forecasts) should bear that in mind.

To be sure, a range of between two and three degrees is higher than the 1.5 degrees that those who drew up the Paris Agreement called a dangerous tipping point, but, if the Earth ends up in 2100 within that range, it will be short of the worst-scenarios. Of course, like all the estimates that have preceded them, these numbers could be too optimistic or too pessimistic, and they likely reflect some steps already taken to reduce carbon emissions — but they are another reason for those predicting catastrophe to exhibit a little modesty.