It is known that volcanic eruptions alter worldwide climate by injecting ash and gases into the atmosphere , which reduce the amount of sunlight reaching the Earth , often causing cold weather and crop failures . The Huaynaputina eruption decreased the amount on solar energy reaching Earth by about . The summer of 1601 was among the coldest in the northern hemisphere during the last six centuries , and the impact may have been comparable to that of the 1815 Tambora eruption . Other volcanoes may have erupted alongside Huaynaputina and also contributed to the weather anomalies ; a number of large volcanic eruptions took place in the decades preceding and following the Huaynaputina eruption
1815 Tambora eruption
1815 eruption of Mount Tambora
Huaynaputina