One of the most common misunderstandings amongst climate deniers is the difference between short-term noise and long-term signal. This video shows how the same temperature data (green) that is used to determine the long-term global surface air warming trend of 0.18°C per decade (red) can be used inappropriately to "cherrypick" short time periods that show a cooling trend simply because the endpoints are carefully chosen and the trend is dominated by short-term noise in the data (blue steps).

Isn't it strange how seven periods of cooling can add up to a clear warming trend over the last 4 decades? Several factors can have a large impact on short-term temperatures, such as oceanic cycles like the El Niño Southern Oscillation (ENSO) or the 11-year solar cycle.

These short-term cycles don't have long-term effects on the Earth's temperature, unlike the continuing upward trend caused by global warming from human greenhouse gas emissions.