Future climatic changes: Are we entering an exceptionally long interglacial?

Various experiments have been conducted using the Louvain-la-Neuve two-dime nsional Northern Hemisphere climate model (LLN 2-D NH) to simulate climate for the next 130 kyr into the future. Simulations start with values represe nting the present-day Northern Hemisphere ice sheet, using different scenar ios for future CO2 concentrations. The sensitivity of the model to the init ial size of the Greenland ice sheet, and to possible impacts of human activ ities, has also been tested. Most of the natural scenarios indicate that: ( i) the climate is likely to experience a long lasting (similar to 50 kyr) i nterglacial; (ii) the next glacial maximum is expected to be most intense a t around 100 kyr after present (AP), with a likely interstadial at similar to 60 kyr AP; and (iii) after 100 kyr AP continental ice rapidly melts, lea ding to an ice volume minimum 20 kyr later. However, the amplitude and, to a lesser extent, the timing of future climatic changes depend on the CO2 sc enario and on the initial conditions related to the assumed present-day ice volume. According to our modelling experiments, man's activities over the next centuries may significantly affect the ice-sheet's behaviour for appro ximately the next 50 kyr. Finally, the existence of thresholds in CO2 and i nsolation, earlier shown to be significant for the past, is confirmed to be also important for the future.