or as carbonate deposited in mollusk shells. Lime is produced in volume for the cement industry. This was assessed in 2022 in an experiment in Apalachicola, Florida in an attempt to halt declining oyster populations. pH levels increased modestly, as was reduced by 70 ppm. A 2014 experiment added sodium hydroxide (lye) to part of Australia's Great Barrier Reef. It raised pH levels to nearly preindustrial levels. However, producing alkaline materials typically releases large amounts of , partially offsetting the sequestration. Alkaline additives become diluted and dispersed in one month, without durable effects, such that if necessary, the program could be ended without leaving long-term effects. Iron fertilization Submarine forest Another 2022 experiment attempted to sequester carbon using giant kelp planted off the Namibian coast. Whilst this approach has been called "ocean geoengineering" it is just another form of carbon dioxide removal via sequestration. Issues Vague meaning of the term According to climate economist Gernot Wagner the term "geoengineering" is "largely an artefact and a result of the terms frequent use in popular discourse" and "so vague and all-encompassing as to have lost much meaning". Moral hazard and ethics Climate engineering may reduce the urgency of reducing carbon emissions, a form of moral hazard. However, several public opinion surveys and focus groups reported either desire to increase emission cuts in the presence of climate engineering, or of no effect. The Union of Concerned Scientists points to the danger that the technology will become an excuse not to address the root causes of climate change, slow our emissions reductions and start moving toward a low-carbon economy. Other modelling work suggests that the prospect of climate engineering may in fact increase the likelihood of emissions reduction. If climate engineering can alter the climate then this raises questions whether humans have the right to deliberately change the climate, and under what conditions. For example, using climate engineering to stabilize temperatures is not the same as doing so to optimize the climate for some other purpose. Some religious traditions express views on the relationship between humans and their surroundings that encourage (to conduct responsible stewardship) or discourage (to avoid hubris) explicit actions to affect climate. Opponents offer several objections: Climate engineering could reduce pressure for emissions reductions, which could exacerbate overall climate risks. Also, most efforts have only temporary effects, requiring ever-increasing interventions which imply rapid rebound if they are not sustained. Others assert