It only took a handful of freak killer storms devastating our economic and cultural capitals for Americans to get real about the perils of global warming. You know who is the most interested in figuring out exactly how bad global warming will be? The people with all the money, who have the most to lose. That is a good reason to tremble in fear at this new World Bank forecast.
We are fucked, is what it comes down to. Whether you read the report itself or any of the various news stories on the report, what you will get is an endless cascade of horror, each element of looming devastation and displacement scarier than the last. The report examines "what the world would be like if it warmed by 4 degrees Celsius, which is what scientists are nearly unanimously predicting by the end of the century, without serious policy changes." This is not just an overblown, worst case scenario; it is a likely scenario. Even great political will—greater than exists—could not cut the warming trend in half, even if we started drastic measures now, which we are not going to do. A warming of 4 degrees Celsius is likely within the century, given "present emission trends." So what are we in for? Some excerpts from the executive summary:
A global warming of 0.8°C [which we already have today] may not seem large, but many climate change impacts have already started to emerge, and the shift from 0.8°C to 2°C warming or beyond will pose even greater challenges. It is also useful to recall that a global mean temperature increase of 4°C approaches the difference between temperatures today and those of the last ice age, when much of central Europe and the northern United States were covered with kilometers of ice and global mean temperatures were about 4.5°C to 7°C lower. And this magnitude of climate change-human induced-is occurring over a century, not millennia.
In other words, we are staring down a temperature change roughly equal to the amount of change that triggered the last ice age. Think of it as the coming Age of Fire (on your house).
Projections for a 4°C world show a dramatic increase in the intensity and frequency of high-temperature extremes. Recent extreme heat waves such as in Russia in 2010 are likely to become the new normal summer in a 4°C world. Tropical South America, central Africa, and all tropical islands in the Pacific are likely to regularly experience heat waves of unprecedented magnitude and duration. In this new high-temperature climate regime, the coolest months are likely to be substantially warmer than the warmest months at the end of the 20th century. In regions such as the Mediterranean, North Africa, the Middle East, and the Tibetan plateau, almost all summer months are likely to be warmer than the most extreme heat waves presently experienced. For example, the warmest July in the Mediterranean region could be 9°C warmer than today's warmest July.
Unlivable, deadly heat will be the new normal summer. Winter in the future will be like your grandparents' summer.
Warming of 4°C will likely lead to a sea-level rise of 0.5 to 1 meter, and possibly more, by 2100, with several meters more to be realized in the coming centuries. Limiting warming to 2°C would likely reduce sea-level rise by about 20 cm by 2100 compared to a 4°C world. However, even if global warming is limited to 2°C, global mean sea level could continue to rise, with some estimates ranging between 1.5 and 4 meters above present-day levels by the year 2300. Sea-level rise would likely be limited to below 2 meters only if warming were kept to well below 1.5°C.
Coastal cities will, quite simply, be inundated. There are not enough sandbags in the world to keep several meters of water out of your oceanfront house.
There will also be ecological collapse, lowered crop yields, food shortages, and war. The reality is that what we can't predict with certainty is even scarier to contemplate. Any of us may, in the end, just have to pack up and leave.
With pressures increasing as warming progresses toward 4°C and combining with nonclimate–related social, economic, and population stresses, the risk of crossing critical social system thresholds will grow. At such thresholds existing institutions that would have supported adaptation actions would likely become much less effective or even collapse. One example is a risk that sea-level rise in atoll countries exceeds the capabilities of con- trolled, adaptive migration, resulting in the need for complete abandonment of an island or region. Similarly, stresses on human health, such as heat waves, malnutrition, and decreasing quality of drinking water due to seawater intrusion, have the potential to overburden health-care systems to a point where adaptation is no longer possible, and dislocation is forced.