IPCC head sees land use changes in temperature rollback
Washington, 31 October (Argus) — Global policy makers can, if determined, limit global temperature rise to 1.5°C, but achieving that goal will require changes in agriculture and other land use, the head of the UN's climate change panel said yesterday.
Intergovernmental Panel on Climate Change chair Hoesung Lee said countries may exceed the expectations of global leaders when they signed the Paris climate accord in 2016. That agreement called for limiting temperature rise to a maximum of 2°C from preindustrial levels and included an aspirational goal of limiting the increase to 1.5°C.
Lee, in a speech at a forum hosted by US think tank Resources for the Future, said negative emissions technologies will create competition for land that can have complex consequences.
"A lot will depend on productivity changes in the agricultural sector, and how bioenergy security relates to land use," said Lee, a Korean economist who was vice chair of the panel for eight years before becoming its head in 2015.
Failing to act has its own set of costs, he said, suggesting that ecosystems may pass their tipping point. Climate change velocity" in a 2°C world is too rapid for many ecosystems to adapt, Lee said. Extreme temperature events in a 2°C world likely would be double those of a 1.5°C rise.
The 2°C temperature rise of the Copenhagen agreement most likely would have required a 70pc cut in 2010 level GHG emissions by 2050, he said, and ending activities that produce GHGs by 2100.
Decarbonization of electricity production and carbon pricing both would be required to meet the goal.
On top of that, he said the production of zero-carbon fuels and scale up of carbon management technology will be difficult. Other obstacles include locked-in infrastructure, difficulties in policy coordination and the desire of investors to avoid high front-end costs.
Ocean carbon sequestration is being considered as one option to achieve negative emissions, he said, along with solar radiation management, which he termed atmospheric modification.
"We do not know the full range of the impact of these methods," Lee said.