Final answer:
El Niño and La Niña are part of ENSO and impact global weather but are not causes of global warming. Global warming is primarily caused by human-induced increases in greenhouse gases that enhance the greenhouse effect. Solar variability is not a significant factor in the current trend of global warming.
Step-by-step explanation:
El Niño and its counterpart La Niña are part of the El Niño Southern Oscillation (ENSO) cycle related to changes in ocean temperature and atmospheric pressure across the equatorial Pacific.
These phenomena can disrupt normal weather patterns, leading to extreme global climatic events. However, it is critical to understand that El Niño or La Niña themselves are not causes of global warming. Instead, global warming is attributed to an enhanced greenhouse effect caused primarily by human actions, such as the burning of fossil fuels, which increases levels of greenhouse gases like carbon dioxide and methane in Earth's atmosphere. This enhanced greenhouse effect is deemed responsible for the long-term uptrend in global temperatures observed during the past 50 years.
Scientific consensus holds that solar variability is not the cause of current global warming, in contrast to fluctuations seen in local weather patterns. The leading cause of contemporary climate change, including global warming, is human-induced factors contributing to the augmented greenhouse effect.