Washington, Ice, and a Changing Climate: A Historical Perspective

The famous painting "Washington Crossing the Delaware" prominently features ice, which played a crucial role in George Washington's military strategy during the American Revolution. According to Alex Robb, an educator at Washington Crossing Historic Park, the extreme cold and ice on the Delaware River on Christmas 1776 were initially impediments. However, they ultimately provided a strategic advantage.

The enemy's assumption that the treacherous conditions made an American crossing impossible granted Washington's army the element of surprise, contributing to their victory at Trenton.

Alex Robb stated that milder weather would likely have resulted in significant resistance outside Trenton.

Winters Past and Present

Historical records, including those maintained by Thomas Jefferson, indicate that winters in America were colder during that era. However, data analyst Jen Brady from Climate Central notes a steady increase in winter temperatures since Washington's time.

Research by Climate Central shows that average winter temperatures in the Philadelphia area are currently 5.5 degrees warmer than in 1970, although cold weather and snow will continue to occur, albeit with reduced frequency.

Ice Cores: A Time Machine to Ancient Atmospheres

Key evidence of climate change comes from ice cores, long tubes of ice extracted from glaciers. These cores contain perfectly preserved air bubbles, with deeper sections holding older air, providing a historical record of atmospheric conditions.

These cores contain perfectly preserved air bubbles, with deeper sections holding older air, providing a historical record of atmospheric conditions.

Eric Steig, a glaciologist at the University of Washington, describes ice cores as a "time machine," allowing scientists to analyze ancient air.

The Industrial Revolution and Rising Carbon Levels

An ice core dating from 1776, for instance, contains air from that period, including carbon dioxide. For 800,000 years, carbon dioxide levels in ice cores did not exceed 300 parts per million.

However, around 1800, carbon levels began a rapid increase. This spike is attributed to the burning of fossil fuels, which intensified with the Industrial Revolution.

Emissions from cars, factories, and power plants have released substantial amounts of carbon dioxide, contributing to warmer temperatures and the intensification of extreme weather events such as floods, droughts, and fires.

Reflecting on History and Future Climate

Steig emphasized the importance of understanding these changes to prepare for future environmental conditions.

The period of Washington's Delaware crossing thus marks both a pivotal moment in American history and the nascent stages of significant climate change, both of which continue to influence the world.