Climate Change and Adaptation: how the past can inform the future

DIANE L. DOUGLAS
Statistical Research Inc., USA

Global warming is one of the most important and dangerous issues facing man today. Many scientists and politicians have focused on anthropogenic causes of this change and the need to reduce CO2 emissions to limit or slow the process. Major climate changes, however, have occurred throughout earth’s history. The shifting of continental plates, rise of mountains, and cyclical changes in earth’s orbit around the sun are primary forcing mechanisms driving climate change. The complex coupling between the atmosphere, ocean, clouds, ice sheets, volcanoes, earthquakes, and the exchange of carbon within living organisms also affect climate. Over the past two million years, earth’s climate has been punctuated by glacial and interglacial periods—periods when earth’s temperature ranged from 8oC cooler to 4oC warmer than present. Hominids adapted their settlements and subsistence practices to these changes. Modern humans evolved around 40,000 years ago, during the last ice age, and at the end of the last ice age migrated to new lands and new continents. People developed new technologies and adaptive strategies in response to sea level rise and a more productive environment. Today we face climate change of a similar magnitude to the last interglacial. This paper shows how natural forcing mechanisms may drive earth into an interglacial as warm as the last interglacial, regardless of reductions in greenhouse gas emissions. Sea level may rise 15 – 20 feet, and in some regions storms will increase in frequency and strength, and in others deserts will expand. Many significant heritage resources are threatened by these changes, and those that cannot be saved should be thoroughly documented to share with future generations. Others may be saved through hazard mitigation measures—but the key lies in engaging the public and governments, which requires convincing them that climate change is inevitable and planning for change is essential.