The phrase “if nothing changes” essentially means that if the status quo remains as it is, which includes the existing programs—in other words, if they're not augmented, if they're not increased, if things just stay the way they are—then given the rates, given the demographics, the prediction is that there will be an increase in federal custody unless measures are taken to either increase programs or undertake other measures to basically bend the curve.
On February 23rd, 2016. See this statement in context.