Luckily, the job security for forensic scientists of all calibers keeps getting better and better, since the technologies that underlie their work become more sophisticated, more precise, and more necessary. New equipment means that new forensic technicians will be brought in and trained to run these new pieces of equipment. Just like what happened with DNA testing a few years back, courts will start to require these new techniques for all of its current cases, and may even reopen old cases for a fresh look. All these extra technologies equal more bodies (the living kind).
Most forensic scientists work for state and local governments, so some of the job opportunities and security also depends on the wealth of the area, as well as the murder rate. A forensic scientist working for a "CSI: NY" will make more money, and may also enjoy more job stability, than the same scientist at, say, a "CSI: Topeka."