secretariat is established under Article8 of the convention and headed by the Executive Secretary. Patricia Espinosa was appointed Executive Secretary on 18 May 2016 by United Nations Secretary-General Ban Ki-moon and took office on 18 July 2016. Espinosa retired on 16 July 2022. UN Under Secretary General Ibrahim Thiaw acts as the acting Executive Secretary in the interim. On 15 August 2022, Secretary-General António Guterres appointed former Grenadian climate minister Simon Stiell as Executive Secretary, replacing Espinosa. Former executive secretaries are: Commentaries and analysis Interpreting article 2 The ultimate objective of the Framework Convention is "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic [i.e., human-caused] interference with the climate system". Article 2 of the convention says this "should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner". To stabilize atmospheric GHG concentrations, global anthropogenic GHG emissions would need to peak then decline (see climate change mitigation). Lower stabilization levels would require emissions to peak and decline earlier compared to higher stabilization levels. The graph above shows projected changes in annual global GHG emissions (measured in CO2-equivalents) for various stabilization scenarios. The other two graphs show the associated changes in atmospheric GHG concentrations (in CO2-equivalents) and global mean temperature for these scenarios. Lower stabilization levels are associated with lower magnitudes of global warming compared to higher stabilization levels. There is uncertainty over how GHG concentrations and global temperatures will change in response to anthropogenic emissions (see climate change feedback and climate sensitivity). The graph opposite shows global temperature changes in the year 2100 for a range of emission scenarios, including uncertainty estimates. Dangerous anthropogenic interference There are a range of views over what level of climate change is dangerous. Scientific analysis can provide information on the risks of climate change, but deciding which risks are dangerous requires value judgements. The global warming that has already occurred poses a risk to some human and natural systems (e.g., coral reefs). Higher magnitudes of global warming will generally increase the risk of negative impacts. According to Field et al. (2014), climate change risks are "considerable" with 1 to 2 °C of global warming, relative to pre-industrial levels. 4 °C warming would lead to significantly increased risks, with potential impacts including widespread