Everything in nature is interconnected. Even a small change in one part of the natural world leads to changes in many others. So, as the temperature on the planet rises, we are seeing many other related changes. The level of the world ocean is rising, glaciers and permafrost are melting, the frequency and power of extreme weather events (heatwaves, hurricanes, storms, floods, and droughts) are increasing year by year. New and dangerous infectious diseases and various pests are appearing in places where they were so far unknown. These and other effects of climate change are dangerous to plants and animals, which cannot adapt quickly to such drastic changes. They also cause enormous economic damage and present a threat to human health and even human life.
The recent findings of the IPCC AR6 show that climate change could lead to even more dangerous consequences for people and for the natural world in the future. The scientists concluded that for every 0.1°C that the planet gets hotter, the impacts get worse, and risks get higher (Fig. 2.1). This is why United Nations Secretary-General António Guterres called this report ‘a code red for humanity’. But on the flip side, every 0.1°C that’s prevented can be crucial in limiting the extent of future damage.
Increased risks with rising temperatures assessed by the IPCC (Fig 2.2) show that even limiting global temperature rise to 1.5°C is not safe for all. At this level of warming, for example, 950 million people across the world’s drylands will experience water stress, heat stress and desertification, while the share of the global population exposed to flooding will rise by 24%.
Figure 2.1 The negative impacts of climate change on the environment and human beings by the end of the 21st century, unless we do all we can to reduce greenhouse gas emissions
Figure 2.2 Comparing risks at different temperature levels on human and natural systems
Today’s climate change will indeed reduce agricultural productivity, limit the availability of freshwater, increase the severity of droughts, heat waves and tropical cyclones, and reshape coastal environments on a speed and scale that could provoke destabilizing societal responses. The WMO established that four key climate change indicators – greenhouse gas concentrations, sea level rise, ocean heat and ocean acidification – set new records in 2022. This is yet another clear sign that human activities are causing planetary-scale changes on land, in the ocean, and in the atmosphere, with dramatic and long-lasting ramifications. Unless we do all we can to reduce greenhouse gas emissions, the negative impacts of climate change on the environment and human beings could well be irreversible by the end of the 21st century (Fig. 2.3).
Figure 2.3 Key risks to natural and human systems stemming from climate change by the end of the century
Experiences suggest that exploring the resilience of past populations to climatic changes and anomalies could provide key insights into valuable solutions on how to cope with climate change today and in the future. To reduce the damage caused by climate change, humanity must take appropriate measures, especially by building resilience to the human-caused warming that is already baked into the current climate crisis. The evidence from impacts so far and projected risks show that worldwide climate-resilient development action is more urgent than now than ever before.
Feasible and effective adaptation measures are presented for each of the themes discussed in this chapter. They include measures which can reduce risk, such as considering climate change impacts and risks in the design and planning of urban and rural settlements and infrastructure. They also include measures which can help to safeguard biodiversity and ecosystems that are critical for climate-resilient development, given the threats climate change poses to them and their roles in adaptation and mitigation (Fig. 2.4).
While we all feel the impacts from climate change already, they most hit the poorer, historically marginalized communities. Scientists noted in the IPCC AR6 report that today, between 3.3 billion and 3.6 billion people live in countries highly vulnerable to climate impacts, mostly in the Arctic, Central and South America, Small Island Developing States, South Asia and much of sub-Saharan Africa. Climate change impacts exacerbate existing conflicts, inequalities, conflict, and development challenges (e.g., poverty and limited access to basic services like clean water) across many countries in these regions, and limit communities’ capacity to adapt. For instance, from 2010 to 2020, mortality from storms, floods and droughts was 15 times higher in countries with high vulnerability to climate change than in those with very low vulnerability.
This section explores the impacts of climate change on various regions, societies, and economic activities, and presents examples of climate adaptation measures that help mitigate and prepare for some unavoidable negative climate impacts.
Climate change-related hazards, risks, impacts, resilience and adaptation
Today, the Intergovernmental Panel on Climate Change (IPCC) uses the term resilience to mean the ability of coupled human and natural systems ‘to cope with a hazardous event or trend or disturbance, responding or reorganizing in ways that maintain their essential function, identity and structure.’
It therefore encompasses adaptation, which the IPCC defines as the process of adjustment to actual or expected climate and its effects, to moderate harm or exploit beneficial opportunities. For example, adaptation measures might include the construction of buildings that are more resistant to extreme weather events, building dams to combat floods, developing new, drought-resistant crop varieties, etc.
The IPCC also widely uses the concept of risks in relation to the potential for adverse consequences from climate change for human or ecological systems, recognizing the diversity of values and objectives associated with such systems. In the context of climate change, risks can arise from potential impacts of climate change as well as human responses to climate change.
The consequences of realized risks from climate change on natural and human systems define the impacts. Impacts generally refer to effects on lives, livelihoods, health and wellbeing, ecosystems and species, economic, social, and cultural assets, services (including ecosystem services), and infrastructure.
Hazards are defined as negative impacts from natural or human-induced physical events or trends that may cause loss of life, injury, or other health impacts, as well as damage and loss to property, infrastructure, livelihoods, service provision, ecosystems, and environmental resources.
Figure 2.4 How to adapt to climate change and build resilience
