“Human interference with the climate system is occurring, and climate change poses risks for human and natural systems.” IPCC WGII AR5
Every five years or so thousands of scientists from around the world release a major report on the state of climate science. These reports from the Intergovernmental Panel on Climate Change (IPCC) are the most definitive source of information for understanding not only the planet’s geologic and climatic history, but how humans are now influencing earth’s systems, most notably by altering the composition of the atmosphere.
The second part of the most recent report, released today in Yokohama, Japan, focuses on the impacts of climate change and how well governments are adapting to those impacts. This newly-released portion of the report, from the IPCC’s Working Group II, does not bode well for the future of people on this planet. The report predicts massively negative effects on crops, extinction of species, devastating heat waves, acid oceans and geopolitical conflict.
And that’s being called a “conservative” outlook.
“We have assessed impacts as they are happening in natural and human systems on all continents and oceans,” IPCC chair Rajendra Pachauri, told Time Magazine. “No one on this planet will be untouched by climate change.”
The impacts of climate change are already upon us, according to the report, affecting “all continents and across the oceans.” In particular, changes in precipitation and melting snow and ice have altered the globe’s hydrological cycle and access to water resources, and numerous species have begun to shift their range in response to changing climates and systems. And while human systems haven’t been as negatively affected by climate change as natural ones, the report emphasizes the unequal distribution of negative impacts, especially on the world’s poor.
“Climate-related hazards constitute an additional burden to people living in poverty, acting as a threat multiplier,” the report states.
The report acknowledges the major “uncertainties” concerning just how and where the effects of climate change will unfold as well as important unknowns regarding the vulnerability of planetary and governmental systems to complex change. Yet the authors agree – the uncertainties of our future only increase as we increase the ‘stressors’ placed on natural environments and the societies that depend on them.
Global climate change is all about reaching thresholds, tipping points and negative feedback loops. Anticipating just what the outcome of a warmer world will be in coming centuries is perhaps beyond even the most sophisticated science. And yet, the report’s authors warn even a slight increase in global temperatures would massively compound the risk of already unstable natural and human systems.
There are five major concerns identified in the report that are ‘integrative,’ meaning they have the capacity to feed negatively off each other due to “dangerous anthropogenic [human-caused] interference with the climate system.”
These five concerns are listed in the report as follows:
1. Unique and threatened systems: Some unique and threatened systems, including ecosystems and cultures, are already at risk from climate change. The number of such systems at risk of severe consequences is higher with additional warming of around 1°C. Many species and systems with limited adaptive capacity are subject to very high risks with additional warming of 2°C, particularly Arctic-sea-ice and coral-reef systems.
2. Extreme weather events: Climate-change-related risks from extreme events, such as heat waves, extreme precipitation, and coastal flooding, are already moderate and high with 1°C additional warming. Risks associated with some types of extreme events (e.g., extreme heat) increase further at higher temperatures.
3. Distribution of impacts: Risks are unevenly distributed and are generally greater for disadvantaged people and communities in countries at all levels of development. Risks are already moderate because of regionally differentiated climate-change impacts on crop production in particular. Based on projected decreases in regional crop yields and water availability, risks of unevenly distributed impacts are high for additional warming above 2°C.
4. Global aggregate impacts: Risks of global aggregate impacts are moderate for additional warming between 1-2°C, reflecting impacts to both Earth’s biodiversity and the overall global economy. Extensive biodiversity loss with associated loss of ecosystem goods and services results in high risks around 3°C additional warming. Aggregate economic damages accelerate with increasing temperature but few quantitative estimates have been completed for additional warming around 3°C or above.
5. Large-scale singular events: With increasing warming, some physical systems or ecosystems may be at risk of abrupt and irreversible changes. Risks associated with such tipping points become moderate between 0-1°C additional warming, due to early warning signs that both warm-water coral reef and Arctic ecosystems are already experiencing irreversible regime shifts. Risks increase disproportionately as temperature increases between 1-2°C additional warming and become high above 3°C, due to the potential for a large and irreversible sea-level rise from ice sheet loss. For sustained warming greater than some threshold, 44 near-complete loss of the Greenland ice sheet would occur over a millennium or more, contributing up to 7m of global mean sea-level rise.
The implications of the report are clear: governments need to get serious about tackling climate change by lowering emissions and making decisions with future “generations, economies, and environments” in mind.
The “risks of climate change can be reduced by limiting the rate and magnitude of climate change,” the authors write. And we should quickly get on the task of limiting emissions – an effort that will “substantially” reduce those risks.
We also need to integrate other sustainable transitions into our efforts to reduce greenhouse gas emissions, according to the report – transitions that will limit additional ‘stressors’ such as habitat destruction, over-exploitation, pollution, the squandering of freshwater resources and the spread of invasive species.
Climate change isn’t happening in a vacuum, but is interacting with these additional negative human impacts on natural systems.
If we want to get better at living on earth, we’re going to have to face not just the difficulties posed by a warming climate, but multiple other ‘uncertainties’ associated with humanity’s wholesale failure to adapt to the challenges of our time: learning to live on a finite planet.
Our transition to a less wasteful, less fossil fuel-reliant globe is urgently required. And governments need to kick that transition into high gear.
Image Credit: NOAA
