The IPCC Third Assessment Report showed a graph labeled "Millennial Northern Hemisphere temperature reconstruction" from a paper by Mann, Bradley and Hughes (MBH98) often called the "Hockey Stick Graph". This graph was different to the IPCC First assessment report which showed global temperature for the past 1000 years, and higher temperatures during the Medieval Warm Period. The graph was thought to show that temperatures between 1000 and 1900 were very different. This was criticized in an article by Stephen McIntyre and Ross McKitrick. In a 2006 letter to "Nature", Bradley, Hughes and Mann claimed the original article had said that they could not be exact.