A Cyclical, Foreseeable, Worsening Threat Heatwaves are a Cyclical Human Rights Risk and States Must Provide a Preventive Public-Law ResponseDuring the first two decades of the twenty-first century, approximately 489,000 heat-related deaths occurred yearly. Admissibility: Heatwave Litigation as Emerging Climate LitigationStanding and admissibility are among the central challenges of climate litigation. Due Diligence Obligations Under Article 2 ECHRCommitments to prevent and adapt to environmental harm are generally understood as obligations of due diligence rather than obligations of result. Similarly, the ECtHR has characterised subsidiary environmental obligations arising from Article 2 as obligations de moyens (Erdal Muhammet, §128). ConclusionThis short piece has explored how heatwaves can no longer be understood as mere natural events, as public powers must address them as foreseeable, cyclical, worsening human rights risks.