A draft of a global scientific review on how human and natural systems are expected to respond to the growing threat of climate change has been leaked and its contents—though not wholly unexpected to those who have followed climate science news in recent years—are nonetheless both alarming and devastating.
Titled, Climate Change 2014: Impacts, Adaptation, and Vulnerability, the leaked document is the draft version of the second installment of the Intergovernmental Panel on Climate Change's latest review of the global scientific consensus on the global warming and climate change.
The IPCC's first installment, released in September, focused on assessing the global scientific community's combined research on the causes, pace, and evidence of planetary climate change. As the title of the leaked draft suggests, the next installment takes a more focused looked at the way the projected climate impacts will play on a variety of the Earth's systems both in the natural world, including the oceans and natural habitats, and those, like agricultural and economic systems, built by human society.
Focusing on what the draft report says about the future of world agriculture and food security, the New York Times reports:
On the food supply, the new report finds […] that over all, global warming could reduce agricultural production by as much as 2 percent each decade for the rest of this century.
During that period, demand is expected to rise as much as 14 percent each decade, the report found, as the world population is projected to grow to 9.6 billion in 2050, from 7.2 billion today, according to the United Nations, and as many of those people in developing countries acquire the money to eat richer diets.
Any shortfall would lead to rising food prices that would hit the world’s poor hardest, as has already occurred from price increases of recent years. Research has found that climate change, particularly severe heat waves, was a factor in those price spikes.
The agricultural risks “are greatest for tropical countries, given projected impacts that exceed adaptive capacity and higher poverty rates compared with temperate regions,” the draft report finds.
Asked by the New York Times, IPCC spokesperson Jonathan Lynn did not dispute the authenticity of the document, but emphasized that it was a "draft" still under review and said, “It’s likely to change.”
This is not the first time that drafts of the IPCC's work have been released without authorization, but many simply acknowledge that the review process—which includes assessments and input from hundreds of scientists and experts working in dozens of countries around the world—makes leaks nearly impossible to avoid.
The report on climate impacts looked specifically at how climate change will impact a range of areas, including fresh and salt water ecosystems, food production and agriculture, economic sectors, human health, conflict and security scenarios, and the interplay of these overlapping dynamics.
Offered with varying degrees of scientific consensus and confidence, what follows is a partial list of the key impacts of climate change contained in the leaked IPCC draft assessment:
Climate change will reduce renewable surface water and groundwater resources significantly in most dry subtropical regions, exacerbating competition for water among sectors
A large fraction of terrestrial and freshwater species faces increased extinction risk under projected climate change during and beyond the 21st century, especially as climate change interacts with other pressures, such as habitat modification, over-exploitation, pollution, and invasive species
Due to sea-level rise throughout the 21st century and beyond, coastal systems and low-lying areas will increasingly experience adverse impacts such as submergence, coastal flooding, and coastal erosion
By 2100, due to climate change and development patterns and without adaptation, hundreds of millions of people will be affected by coastal flooding and displaced due to land loss
Ocean acidification poses risks to ecosystems, especially polar ecosystems and coral reefs, associated with impacts on the physiology, behavior, and population dynamics of individual species
Without adaptation, local temperature increases of 1°C or more above preindustrial levels are projected to negatively impact yields for the major crops (wheat, rice, and maize) in tropical and temperate regions, although individual locations may benefit
Heat stress, extreme precipitation, inland and coastal flooding, and drought and water scarcity pose risks in urban areas for people, assets, economies, and ecosystems, with risks amplified for those lacking essential infrastructure and services or living in exposed areas
Major future rural impacts will be felt in the near-term and beyond through impacts on water supply, food security, and agricultural incomes, including shifts in production of food and non-food crops in many areas of the world
Global mean temperature increase of 2.5°C above preindustrial levels may lead to global aggregate economic losses between 0.2 and 2.0% of income
Until mid-century, climate change will impact human health mainly by exacerbating health problems that already exist (very high confidence), and climate change throughout the 21st century will lead to increases in ill-health in many regions, as compared to a baseline without climate change
Climate change indirectly increases risks from violent conflict in the form of civil war, inter-group violence, and violent protests by exacerbating well-established drivers of these conflicts such as poverty and economic shocks
Throughout the 21st century, climate change impacts will slow down economic growth and poverty reduction, further erode food security, and trigger new poverty traps, the latter particularly in urban areas and emerging hotspots of hunger