Glossary of Climate Change - H

H

• Heiligendamm Process - an initiative that will institutionalize high level dialogue between the G8 countries and the five most important emerging economies, known as the O5 (Outreach 5) composed of China, Mexico, India, Brazil and South Africa; and the establishment of a common G5 + G8 platform at the OECD.
• Historical temperature record - see temperature record.
• Hockey stick controversy - a dispute over the reconstructed estimates of Northern Hemisphere mean temperature changes over the past millennium, frequently referred to as the MBH98 reconstruction.
• Holocene - a geological period, which began approximately 11,550 calendar years BP (about 9600 BC) and continued to the Anthropocene.
• Holocene Climatic Optimum - a warm period during roughly the interval 9,000 to 5,000 years B.P.