Climate Change: The New Normal Management

Introduction: Climate Change As A New Normal

The atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased to unprecedented levels during the past 800,000 years (IPCC, 2013). Such an increase in the level of greenhouse gases has significantly affected normal weather events like daily temperatures. As a result, the world is warming at a rate three times that of the 1880s (IPCC, 2018). Also, global warming has significantly enhanced the frequency and intensity of high-temperature extremes (Figure 1), i.e., heatwaves, in some parts of the world, e.g., western and central United States, West Africa, and Australia (IPCC, 2021). Heatwaves have caused more deaths for humans than any other extreme event or natural disaster. However, dealing with extreme heatwaves is very difficult in our changing world.

Figure 1.

Number of natural global disasters by year. (Own representation based on EMDAT, 2021).

While changes in the temperature have already influenced a diverse set of physical and biological systems, the global average surface temperature is projected to rise about 2.1 to 5.7°C up by 2100, compared with the pre-industrial level (IPCC, 2021). Global warming is expected to be associated with the change of seasonality, increase in the average, maximum and minimum seasonal temperatures, increase in the frequency and intensity of heatwaves, reduction of soil moisture, and worsening of water shortage in the arid and semi-arid regions of the world (IPCC, 2021; Karimi et al., 2018).

Global warming has also led to a change in precipitation patterns. Large multi-year oscillations in precipitation have been more frequent and extreme after the late 1960s relative to the preceding decades (Figure 1), and the precipitation patterns across some regions have settled around a new norm (IPPC, 2013). The shift in the precipitation patterns declares that we can no longer rely on historical data to predict reliable rainfall patterns for our future. Moreover, the number of catastrophic events, such as floods, storms, and droughts, have significantly increased over the past four decades (Figure 1). Also, there is a considerable body of evidence, which suggests that almost every storm, drought, flood, wildfire, and heatwave are more destructive than the previous ones (Figure 2). This condition can be described as a transition to a new normal, at least from the precipitation perspective.

Figure 2.

Extent of damages (* 1 million 2016 US$): 1964-2020 (own reperesentation on EMDAT, 2021)

Warming-induced drying over the northern mid-high latitudes and ENSO-induced precipitation with drier conditions over most regions of Africa, Southeast Asia, eastern Australia, southwest United States, and southern Europe have increased the areas under drought by about 8% in the 21^st century (Dai, 2013, Haile et al., 2020). Many regions, i.e., Australia, India, Indonesia, Philippines, Iran, Brazil, some parts of eastern and southern Africa, Central America, and the United States, have experienced their worst droughts in decades, which have affected hundreds of millions of people. Climate change is projected to increase the frequency and severity of droughts in arid and semi-arid regions, e.g., the central and southern United States, southern Australia, Southeast Asia, and southern Africa, by the end of this century. Also, the nature of droughts is expected to change, with a greater frequency of long lasted and extreme droughts and less frequent short-term and moderate to severe droughts (IPCC, 2021).