### Measuring ocean heating is key to tracking global warming

Human emissions of greenhouse gases such as carbon dioxide are causing the Earth to warm. We know this, and we have known about the heat-trapping nature of these gases for over 100 years.

### A reduction in marine primary productivity driven by rapid warming over the tropical Indian Ocean

Among the tropical oceans, the western Indian Ocean hosts one of the largest concentrations of marine phytoplankton blooms in summer. Interestingly, this is also the region with the largest warming trend in sea surface temperatures in the tropics during the past century—although the contribution of such a large warming to productivity changes has remained ambiguous. Earlier studies had described the western Indian Ocean as a region with the largest increase in phytoplankton during the recent decades.

### No iron fertilization in the equatorial Pacific Ocean during the last ice age

Core isotope measurements in the equatorial Pacific Ocean reveal that although atmospheric dust deposition during the last ice age was higher than today’s, the productivity of the equatorial Pacific Ocean did not increase; this may have been because iron-enabled greater nutrient consumption, mainly in the Southern Ocean, reduced the nutrients available in the equatorial Pacific Ocean, and hence also productivity there.

### On the decreasing trend of the number of monsoon depressions in the Bay of Bengal

This study unravels the physical link between the weakening of the monsoon circulation and the decreasing trend in the frequency of monsoon depressions over the Bay of Bengal. Based on the analysis of the terms of Genesis Potential Index, an empirical index to quantify the relative contribution of large scale environmental variables responsible for the modulation of storms, it is shown here that the reduction in the mid-tropospheric relative humidity is the most important reason for the decrease in the number of monsoon depressions.

### Earth system commitments due to delayed mitigation

As long as global CO2 emissions continue to increase annually, long-term committed Earth system changes grow much faster than current observations. A novel metric linking this future growth to policy decisions today is the mitigation delay sensitivity (MDS), but MDS estimates for Earth system variables other than peak temperature (ΔT max) are missing.

### 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.

### Carbon dioxide causing 'intoxication' of ocean fish sooner than expected

UNSW's Ben McNeil and Tristan Sasse explain how a rise in the oceans' CO2 levels could have huge implications for global fisheries and marine ecosystems.

### 2015 declared the hottest year on record

It’s official: 2015 was the hottest year on record. Global data show that a powerful El Niño, marked by warmer waters in the tropical Pacific Ocean, helped to drive atmospheric temperatures well past 2014's record highs. Some researchers suggest that broader Pacific trends could spell even more dramatic temperature increases in years to come.

### 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.

### World's oceans warming at increasingly faster rate, new study finds

The world’s oceans are warming at a quickening rate, with the past 20 years accounting for half of the increase in ocean heat content that has occurred since pre-industrial times, a new study has f