This is not true. Given that temperature and co2 rise sync with each other(still debated) and OA are fairly synchronous, the steep decline and subsequent rise in temperature from appx. 8400ya - 8000ya(Vinther, B., et al., 2009) exceeds what we are seeing now. Notably that fall and rise was at a much higher temperature as well. I can only assume this has happened many many times previously.