All Observed Effects:
- Are an explicit finding of a long-term (20+ years) trend with a clear (direct or reasonably implied) negative impact on humans.
- Connect this observation to warming, or related climatic trends. Effects from CO2 itself (e.g. ocean acidification) or other forms of pollution are excluded.
- Are based primarily on observed, empirical evidence: no model simulations, predictions, or short-term experiments.
- Are peer-reviewed studies from reputable journals, and focused in their scope.
Images courtesy USGS.