If the greenhouse effect is natural, then why is today's climate change a bad thing? A.)A small increase in greenhouse gas concentration can have a large effect of increased warming.
B.)Humans have altered a natural process and exaggerated changes that might normally occur over millions of years.
C.)Once released into the atmosphere, greenhouse gases remain potent for many years, making it difficult to reverse the process.
D.)Abrupt changes to the climate system may have unintended outcomes that may pose challenges for societies, like more extreme weather, spread of diseases, a decline in marine life, or an alteration of ocean circulation patterns.
E.)All of these