The effects of climate change are already occurring on all continents and across the oceans, according to a new report from the Intergovernmental Panel on Climate Change (IPCC). Moreover, in many cases the world is ill-prepared for risks resulting from a changing climate and the IPCC believes that increasing magnitudes of warming will increase the likelihood of severe and pervasive impacts that may be surprising or irreversible.

The key risks identified in the report concern storm surges, coastal flooding, and sea-level rise for coastal communities; disruption and ill-health due to inland flooding in some regions; systemic risks due to extreme weather events leading to breakdown of infrastructure networks and critical services such as electricity, water supply, and health and emergency services.

Climate Change 2014: Impacts, Adaptation, and Vulnerability, the fifth and most rigorous assessment report from the IPCC, states that there are opportunities to respond to such risks, though it stresses that the risks will be difficult to manage with high levels of warming.

A total of 309 coordinating lead authors, and review editors, drawn from 70 countries, worked together to produce the report along with 436 contributing authors, and a total of 1,729 expert and government reviewers.

“We live in an era of man-made climate change,” said Vicente Barros, co-chair of Working Group II. “In many cases, we are not prepared for the climate-related risks that we already face. Investments in better preparation can pay dividends both for the present and for the future.”
Impacts from recent climate-related extremes, such as heat waves, droughts, floods, cyclones, and wildfires, reveal significant vulnerability and exposure in ecosystems and human systems to current climate variability, the report says.

Food production disruption

As well as causing damage to infrastructure and settlements, morbidity and mortality, climate extremes will result in the alteration of ecosystems, the disruption of food production and water supply, the report adds.

After studying a wide range of regions and crops, the report’s authors conclude with high confidence that negative impacts of climate change on crop yields have been more common than positive impacts.

Climate change has negatively affected wheat and maize yields for many regions and in the global aggregate, for example. Since the IPCC’s last report, several periods of rapid food and cereal price increases following climate extremes in key producing regions indicate a sensitivity of current markets to climate extremes among other factors.

Water security is another risk highlighted by the report. In many regions, changing precipitation or melting snow and ice are altering hydrological systems, affecting water resources in terms of quantity and quality, it says.

As global warming increases so do the risks, the report warns. Some risks of climate change are considerable at 1° or 2°C above preindustrial temperature levels. But global climate change risks are “high to very high” with a global mean temperature increase of 4°C or more above preindustrial levels. The risks include severe and widespread impacts on unique and threatened systems, substantial species extinction, large risks to global and regional food security, and the combination of high temperature and humidity compromising normal human activities, including growing food or working outdoors in some areas for parts of the year.

Adaptation will play a key role in decreasing climate change risks, because so many risks are already “baked into the climate system” due to past emissions and existing infrastructure, the report says. “Understanding that climate change is a challenge in managing risk opens a wide range of opportunities for integrating adaptation with economic and social development and with initiatives to limit future warming,” said Chris Field, co-chair of Working Group II at the IPCC.

Trevor Maynard, Lloyd’s head of exposure management and reinsurance, believes that policymakers must heed the warnings contained in the IPCC’s report: “First and foremost we must reduce our greenhouse gas emissions significantly and effectively,” he says. “Climate change is already making some disasters more likely to happen. However we have decades of unavoidable climate change to come and for this we have to adapt to the changing risks.”