### A framework to understand the transient climate response to emissions

Global surface warming projections have been empirically connected to carbon emissions via a climate index defined as the transient climate response to emissions (TCRE), revealing that surface warming is nearly proportional to carbon emissions.

### Future ocean hypercapnia driven by anthropogenic amplification of the natural CO2 cycle

Data-based projections suggest that the natural CO2 cycle could be amplified by up to ten times by 2100 in some oceanic regions if atmospheric CO2 concentrations continue to increase, which could detrimentally affect major fisheries.

### Climatic modulation of recent trends in ocean acidification in the California Current System

Researchers reconstruct the evolution of ocean acidification in the California Current System (CalCS) from 1979 through 2012 using hindcast simulations with an eddy-resolving ocean biogeochemical model forced with observation-based variations of wind and fluxes of heat and freshwater. Researchers find that domain-wide pH and ${{\rm{\Omega }}}_{\mathrm{arag}}$ in the top 60 m of the water column decreased significantly over these three decades by about −0.02 decade−1 and −0.12 decade−1, respectively.

### Industrial-era global ocean heat uptake doubles in recent decades

Formal detection and attribution studies have used observations and climate models to identify an anthropogenic warming signature in the upper (0–700 m) ocean. Recently, as a result of the so-called surface warming hiatus, there has been considerable interest in global ocean heat content (OHC) changes in the deeper ocean, including natural and anthropogenically forced changes identified in observational, modelling and data re-analysis studies.

### Regional variability of a projected sea ice‐free Arctic during the summer months

Climate projections of sea ice retreat under anthropogenic climate change at the regional scale and in summer months other than September have largely not been evaluated. Information at this level of detail is vital for future planning of safe Arctic marine activities. Here the timing of when Arctic waters will be reliably ice free across Arctic regions from June to October is presented.