资源环境科技发展态势分析平台

The first-ever comprehensive scientific assessment of the links between land and climate change is a critical contribution to efforts to curb greenhouse gas emissions, tackle the impacts of global warming and protect food security, the World Meteorological Organization said today.

The release of the Intergovernmental Panel on Climate Change's Special Report on Climate Change and Land is the culmination of a two-year analysis by more than a hundred of scientists from around the globe who provided their expertise as authors and reviewers.

“The Special Report on Climate Change and Land is a highly important contribution to addressing the interplay between climate change, desertification, land degradation, sustainable land management, food security and greenhouse gas fluxes in terrestrial ecosystems,” said WMO Secretary-General Petteri Taalas.

The IPCC, whose parent organizations are WMO and UN Environment, pools the best in international scientific expertise. Its authors, who work for IPCC on a volunteer basis, assess a wide range of published scientific literature on climate system, climate risks, the costs of inaction and potential solutions.

The report underlines that agriculture, forestry and other types of land use account for 23% of greenhouse gas emissions caused directly or indirectly by human activities. It also notes that natural and managed land systems absorb carbon dioxide equivalent to almost a third of carbon dioxide emissions from fossil fuels and industry.

Monitoring concentrations of the main greenhouse gases in the atmosphere is a core element of WMO’s work.

Its Global Atmosphere Watch programme provides data that helps to protect human health, agricultural productivity and food security. The programme’s observations on the increase in concentrations of carbon dioxide and other heat-trapping gases are incorporated into the annual Greenhouse Gas Bulletin which, like IPCC reports, informs decision makers at UN climate change negotiations.

WMO is now pioneering an Integrated Global Greenhouse Gas Information System – known for short as IG3IS – to provide a bridge between science and policy on greenhouse gas emission, and the identification and quantification of "sinks" that absorb such gases.

“Understanding the Earth system and the complex interactions between and within the atmosphere, ocean, land, cryosphere, biosphere, and human activities, across space and time scales is the core of WMO’s mission,” said Mr Taalas.

“Combined atmosphere, ocean, land and cryosphere predictive models are critical to the improved accuracy of forecasts and to enhance the full spectrum of services to support the protection of life, health, security of food production and water resources. “

The Special Report on Climate Change and Land was released to the public a day after it was approved on 7 August by the IPCC's member governments.

It highlights the fact that that land is already undergoing human pressure and that climate change is adding to these pressures, meaning that better land management is essential.

In 2015, governments backed the Paris Agreement goal of strengthening the international response to climate change by holding the increase in the global average temperature to well below 2ºC above pre-industrial levels and to pursue efforts to limit the increase to 1.5ºC.

The IPCC report says that  keeping global warming under 2ºC – if not 1.5 ºC, as set out in its special report issued last October, which WMO called a "wake-up call" – can be achieved only by reducing greenhouse gas emissions from all sectors, including land and food.

Land must remain productive to maintain food security as the population increases and the negative impacts of climate change on vegetation increase. This means there are limits to the contribution of land to addressing climate change, for instance through the cultivation of energy crops and afforestation. It also takes time for trees and soils to store carbon effectively. Bioenergy needs to be carefully managed to avoid risks to food security, biodiversity and land degradation.

When land is degraded – for example through desertification, or because heavy rain causes soil erosion – it becomes less productive. That in turn restricts what can be grown, putting food security at risk, and also reduces the soil’s ability to absorb carbon. This exacerbates climate change, while climate change in turn exacerbates land degradation in many different ways.

Roughly 500 million people live in areas that experience desertification. Drylands and areas that experience desertification are also more vulnerable to climate change and extreme events including drought, heatwaves, and dust storms, with an increasing global population providing further pressure.

Helping countries prepare for the growing risk of such natural hazards and cope with their impacts is a critical part of WMO's work, through programmes including the Sand and Dust Storm Warning Advisory and Assessment System, the Integrated Drought Management Programme, and a range of other climate services tackling challenges for agriculture, water and health.

“In the wake of the IPCC’s special report on global warming of 1.5 degrees, at WMO we have been stepping up our work to help to fill knowledge gaps, to build the continuum of science that is needed, and to provide the advice required,” said Mr Taalas.

Annual WMO assessments on climate-related topics, which include the flagship Statement on the State of the Climate, all feed into the IPCC’s work. In June, the 18^th World Meteorological Congress adopted a number of important decisions on increasing the support of WMO to IPCC assessments. It also paved the way for greater coordination between the IPCC processes and those of the World Climate Research Programme, which WMO co-sponsors with IOC-UNESCO and the International Science Council.