When did the first volcanic eruption affect global climate measurements?

The eruption of Mount Tambora in April 1815 was one of the most powerful eruptions in recorded history. It blasted so much ash and sulfur into the atmosphere that temperatures dropped worldwide, contributing to the cold, abnormal weather of 1816 known as the Year Without a Summer. Harvests failed in parts of Europe and North America, showing that a single volcano can influence climate on a global scale. Tambora remains a landmark event in both volcanology and climate history.