Saturday, October 30, 2021

The Consequences of Climate Change


Yet another pessimistic report from a think tank.

The world’s largest economies will suffer severe human and economic consequences of climate change, especially if no action is taken to reduce greenhouse gas (GHG) emissions, according to a new study from the Euro-Mediterranean Center on Climate Change (CMCC), an Italian research center.

“From droughts, heatwaves and sea level rise, to dwindling food supplies and threats to tourism — these findings show how severely climate change will hit the world’s biggest economies, unless we act now,” said Donatella Spano, senior member of the CMCC’s Strategic Council and a scientist at the University of Sassari. “As scientists, we know that only rapid action to tackle emissions and adapt to climate change will limit the severe impacts of climate change,” Spano explained.

It found that climate change impacts such as extreme heat and sea level rise are already causing death and destruction in the world’s leading economies, and that if climate change continues unabated, it will also lead to new plagues that proliferate in warmer climates. With medium to high emissions, as temperatures rise in the northern U.S., the Zika virus — which has previously been locally transmitted within the country only in Florida and Texas — could threaten 83 percent of the population by 2050. More than 92 percent of U.S. residents could be at risk from dengue fever.

If emissions remain high, Europe will have 90,000 deaths from extreme heat each year by the end of this century, up from 2,700 currently.

All of this has economic implications too. In a high-emissions future, countries such as France and Indonesia might lose one-fifth or more of their fishing catch due to warmer ocean temperatures, and sea level rise could wreck coastal infrastructure, resulting in projected losses of 404 billion euros ($468 billion) for Japan and 815 million euros ($945 billion) for South Africa by 2050.


On the U.S., the CMCC report said:

  • Under a low emissions scenario projected temperature variations will remain contained at around +1.5°C, both by 2050 and 2100. Under a high emissions scenario, with no reduction in GHG emissions, much greater temperature anomalies are expected by both 2050 and 2100.
  • Considering the different scenarios, precipitation trends show a general increase in annual precipitation at a country level. Higher increments are reported under a high emissions scenario even if characterized by higher variability with respect to the historical period and to the other scenarios.
  • Rising temperatures, reduction in average annual precipitation, and intensification of extreme events such as heat waves and drought, affect production variability with a tendency towards yield reduction for many cultivated species, accompanied by a probable decrease in food quality. Crops respond to increases in temperatures with changes in duration of the growing season, early appearance of phenological phases and potential shifts of cultivation areas toward higher latitudes and altitudes for better growing conditions. However, impacts vary significantly depending on the geographical area and specific crops in question.
  • Climate change is expected to have an impact on the productivity of several major crops, although this may in part be offset by the fertilizing effect of higher CO₂.
  • Climate risks imply substantial increases in water demand (up to 30-35% in some areas) to maintain agriculture production, which will require adaptation practices and crop varieties enhancing water-use efficiency to limit increasing stress on water resources.
  • The duration of individual heatwaves and the heatwave season have also been increasing, along with heatwave intensity. Future scenarios of 1.5°C, 2°C and 4°C mean temperature increases indicate that heatwaves will last longer throughout the entire country.
  • Heat related health impacts from increasing air temperatures in urban areas are furthermore accentuated by air pollution. Wildfires, on the rise in the West, contribute to lower air quality in cities near the wildland–urban interface.
  • In 2018, there was a 54% increase in heat-related deaths in the U.S. compared to the 2000 to 2004 baseline. 34.7% of U.S. heat-related mortality from 1991 to 2006 can be attributed to human-induced climate change.
  • Under a medium emissions scenario, annual premature deaths due to long-term exposure to near-surface ozone and heat will increase from 299 per million (2010) baseline, to 307 per million in 2050.
  • With only 5% of the world’s population the U.S. uses nearly 17% of the world’s energy. In 2018, transport claimed 40% of energy demand – mainly to fuel road transport. The industrial sector claims over 17% of energy demand, almost at par with the residential sector. The tertiary sector accounts for 13.6% of final energy demand; energy use in agriculture and forestry is negligible. Air conditioning accounts for a substantial share of final residential electricity, 26.4%.
  • Hotter summers are boosting air conditioning use, resulting in more frequent and longer power outages. The Southwest blackout at the end of the summer of 2011 left 2.7 million people without power for 12 hours.
  • Warmer summers are predicted to increase electricity demand, resulting in higher summer peak loads. Milder winters are expected to decrease energy demands for heating, but by a smaller scale than the increase in summer cooling needs. Overall, net energy demand is predicted to increase. Higher temperatures might affect the energy mix, reducing demand for oil and natural gas used to heat homes, and instead increasing electricity demand for cooling needs.
  • The USA has the largest economy in the world in terms of GDP. The COVID 19 pandemic reduced growth rates in 2020, whereby the U.S. lost 3.5% of real GDP. However, it has recovered quickly with a growth rate of 6.4% in 2021.
  • Climate change will have an effect on the growth rate and overall systematic economic performance of the country. National losses in GDP may be significant, reaching 2.4% of GDP or 415 billion EUR by mid century under a low emissions scenario, and drastically rising to 10.5% of GDP, or 1.8 trillion EUR, under a high emissions scenario by the end of the century. The costs of climate change are borne unequally across the US, exacerbating pre-existing inequality.
  • By the end of the century, under a high emissions scenario the poorest counties are likely to experience substantial damages in the range of 2-20% compared to gains exceeding 10% of county income in some regions.
  • As a result of climate change, the expected damage from hurricanes is predicted to increase in the future for the U.S. Probabilistic estimates of the damages caused by hurricanes and coastal storms show that there could be additional damages amounting to 108 billion USD by the end of the century. Natural disasters are already imposing significant costs on the U.S., whereby in 2017 there were 300 billion USD worth of damage to homes, businesses, infrastructure and goods.
  • The agricultural sector in the U.S. is significant, producing almost 330 billion USD in agricultural commodities annually. The forestry sector is an important contributor to wealth production, providing a range of important goods and services from timber products to places of recreation. Wildfires in particular will pose a risk to the majority of the U.S. It is estimated that mitigation efforts could save the USA’s economy between 8.6 and 11 billion USD in wildfire costs relative to a business-as-usual scenario until 2100.
  • Expected effects on crop yields are highly heterogeneous across crops and regions. This tendency leaves the aggregate damage estimates quite modest relative to the size of the U.S. economy, and potentially some benefits from climate change could be experienced.
  • Some estimates place the damage to crop yields under a high emissions scenario in the range of -8.2 to +19 billion USD by mid century and -12 to +53 billion USD by the end of the century. More recent studies emphasize smaller potential gains.
  • Nevertheless, damage from extreme weather events may be substantial. The EPA estimates that greenhouse gas mitigation measures could avoid damage of up to 6.6 to 11 billion USD in the agricultural sector by 2100 compared to a business-as-usual scenario, and additionally 0.52 billion to 1.5 billion USD in the forestry sector.


On China, the report said:

  • Precipitation trends show a clear tendency to increase, under all emissions scenarios, with a large variability among the involved models and with respect to the reference period. Increase in precipitation is much greater under a high emissions scenario and longer time ranges.
  • Relative sea level rise has been observed over the past century in China, with an average increase of 2.18 millimeters per year during the past century and approximately 3.4 millimeters per year since 1995. The latest IPCC projections indicate that, by 2050, global sea levels may rise between 0.18 meters, under a low emissions scenario, and 0.23 meters, under a high emissions scenario.
  • China’s coasts, in particular its industrialized and heavily populated delta megapolis, are at high risk from sea level rise and storm surges. With urban settlements typically located and developed along shorelines and river estuaries, these are at high risk from flooding, particularly during the wet season.
  • The Chinese coast is densely populated, and the Pearl River Delta and the Yangtze River Delta are both some the most exposed areas and home to approximately 300 million people and a GDP of 3.4 trillion USD.
  • Climate change and sea level rise is increasing the probability of coastal flood occurrence, vulnerability and risk. Under a medium emissions scenario the total population exposed to the annual coastal flood level is expected to increase from 23 million to 30 million by 2050.
  • Rice is the dominant crop in the south; wheat is found in most provinces, but particularly in eastern regions; maize cultivations are found from the northeast to the southwest; and sugarcane extends mainly over southern to central regions. Other crops include potatoes, sugarbeets, and various other vegetables and fruits. Major cash crops include mandarins in the south and apples and pears in the north. Food crop production helped keep undernourishment levels below 2.5% of the total population in 2018. However, water withdrawal for agriculture is substantial and accounted for 64.4% of total water withdrawal in 2015, in a country where water stress is estimated to stand at 43%.
  • The magnitude of change in crop productivity for main cereals in China commonly varies between + and – 20%. General increases in wheat productivity are expected throughout China, with the largest gains in the eastern plains. Similar gains in productivity are projected for rice, although these will not be as pronounced as for wheat. Most positive increases in rice productivity are expected in northeastern China, whereas decreases are expected in central China.
  • A general decline of productivity is projected for maize in East and Central China, and for sugarcane throughout most of its growing region. Increased occurrence of severe droughts would double drought-related yield losses under a high emissions scenario. Widely cultivated fruit and tree crops such as citrus will witness climate related risks to productivity increasing from southeast to northwest, with yield losses mostly associated with seasonal water shortages.
  • China’s urbanization rate has seen a sharp rise from 16.2% in 1960 to 61.4% in 2020. Now, growth of urbanization rates and of absolute size of urban population is gradually slowing down, with urbanization rate expected to reach 80% by 2050. Urbanization is fuelled by high rates of migration. Climate change induced migration to cities may occur due to those for whom farming becomes an unviable livelihood.
  • Just over 10% of the population is living in one of the six megacities with more than 10 million inhabitants, and a quarter of the population lives in urban areas between 1 and 5 million inhabitants. While the share of population living in cities with more than 1 million inhabitants is expected to grow further, smaller cities, and in particular those with less than 300,000 inhabitants, will decrease slightly.
  • Growth rates of urbanization rates and of absolute size of urban population is gradually slowing down, with urbanization rate expected to reach 80% by 2050. Built up areas cover 2.66% of China (248,533.59 square kilometers), although densities along the coastline and in the north-eastern plain are much higher.
  • Under a medium emissions scenario, the increases in heatwave-related excess mortality will be around 87%. In 2018, there was a 45% increase in heat-related deaths, compared to the 2000-2004 baseline period. 21.3% of heat-related mortality in China from 2003 to 2008 can be attributed to human-induced climate change.
  • A recent study finds that the decrease in heating demand is going to be more than compensated by the increase in cooling needs, resulting, by the end of the century, in a net increase of electricity demand of 16,603 PJ (or 4612 billion KWh) in 2050 under a medium emissions scenario.
  • China is the third largest economy of the G20 group and the one showing the highest GDP growth rates.
  • In a vast area like China, economic impacts from climate change can be extremely different from region to region. Thus the national average clearly provides only a very aggregated view of climate change costs.
  • This said, under more moderate climate change scenarios like a low emissions scenario, some net gains may occur. Indeed by mid century, economic effects range from a potential gain of 98 billion EUR (0.8% of GDP) to a loss of 195 billion EUR (1.6% of GDP).
  • However, potential gains vanish with time and, in the second half of the century, China is expected to experience a net loss also under a low emissions scenario. Under a high emissions scenario GDP effects are unambiguously negative and could reach a loss of 772 billion EUR (or more than 6% of GDP).
  • China’s extensive manufacturing industry produces 12% of global exports and accounts for 32% of national GDP. By mid-century, climate change is predicted to reduce production in the manufacturing industry by 12% if no adaptation measures are implemented. This translates to a loss of about 33 billion EUR and a 4% decline in annual GDP.
  • As temperatures increase, and in the absence of any further adaptation measures, more people will be exposed to flooding risks, and the economic costs are projected to increase drastically. China is particularly vulnerable to damages from the flooding of its river basins.


On Japan, the report said:

  • Japan ranks 4th in terms of GDP among G20 economies. Japan was badly affected by the COVID crisis, recording a decline of 4.8% in real GDP in 2020. In 2021 this trend has reversed and the country has seen 3.3% growth.
  • There is a noticeable variability across estimates of the overall economic impact of climate change for Japan, although estimates under similar assumptions tend to converge across studies.
  • The projected overall macroeconomic impacts for Japan range from moderate GDP losses (0.8 %) under a low emissions scenario in 2050, to a loss larger than 10 % under a high emissions scenario by the end of the century.
  • Japan features the 7th longest coastline in the world. Just under half of its population, and about the same proportion of industrial production, is vulnerable to an increase in sea level, due to the increased risk of coastal erosion, storm surges and typhoons.
  • Within the service macro-sector, the main economic impacts will likely affect trade and transportation. Japan’s economy and manufacturing sector are based on highly sophisticated technologies, requiring a wider array of inputs which are usually not produced domestically, but imported. This dependence from imports may also be an important source of climate vulnerability.
  • For instance, it is estimated that 17% of Japanese imports during the period 2008-2018 originated from countries heavily threatened by climate change. At the same time, Japan could benefit from a possible opening of the transpolar Arctic route for freight transport, which would reduce its distance from northern Europe by 37%. However, the actual viability of such a route might be severely limited by safety and environmental factors, and hence the benefits, if any, might be very limited.
  • The economic losses induced by projected sea level rise in Japan are massive. Assuming constant levels of coastal protection, in the low emissions scenario asset losses could reach 203 and 537 billion EUR in 2050 and 2070, respectively.
  • Under a high emissions scenario losses could increase to 404 and 1,255 billion EUR in 2050 and 2070.


On Germany, the report said:

  • The history of German forests is strongly linked to human intervention and is still largely shaped by the massive reforestation efforts carried out after the devastation of the Second World War. Almost all German forests are considered secondary forests with a prevalence of conifers, although deciduous temperate species such as beech and oak are constantly increasing.
  • Despite being a very populous country, forests in Germany cover over 30% of the land surface with a very stable trend in recent decades. According to the Third National Forest Inventory, more than 1,100 million tons of carbon are stored in living trees and deadwood removing approximately 52 million tons of CO₂ from the atmosphere every year. Forests are currently considered an important carbon sink for the country.
  • Germany ranks first the Eurozone and fourth in the G20 group for GDP. The country recovered quite well after the 2008-2009 economic crisis showing, in the 2010-19 period, an average annual real GDP growth rate of roughly 1.9%. It has been hit severely by the COVID crisis, recording a decline of nearly 5% in real GDP growth rate in 2020.
  • Despite its developed and technology-rich economy, Germany may face no to marginal systemic losses and negative growth impacts from climate change. GDP losses can be significant already by mid century under a low emissions scenario peaking at 1.35% of GDP or 45 billion EUR.
  • They can more than double reaching 98 billion EUR or nearly 3% of GDP by the end of century under a high emissions scenario.
  • In the second half of the century, if coastal defenses are not upgraded to contrast increasing climate change risk, expected annual damages to coastal infrastructure could reach more than 74 billion EUR under a high emissions scenario.


On India, the report said:

  • Under a low emissions scenario projected temperature variations will remain contained under +1.5°C, both by 2050 and 2100. Under a high emissions scenario, with no reduction in GHG emissions, much greater temperature anomalies are expected by both 2050 and 2100.
  • Precipitation trends show a very complex signal, under all emissions scenarios, with a very large variability among climate models. This can be explained considering the complexity of the precipitation regime and dynamics requiring more detailed spatial and temporal analysis.
  • Relative sea level rise has been observed over the past century around the coast of India, with a yearly average increase of approximately 1.56 millimeters per year since the 1990s. The latest IPCC projections indicate that, by 2050, global sea levels may rise between 0.18 meters, under a low emissions scenario, and 0.23 meters, under a high emissions scenario.
  • On average, one in 100 extreme sea level events are expected to rise from 2.05 meters at present day to 2.23 meters by 2050 under a medium emissions scenario.
  • Waves and storms around the Indian coast are expected to change in the future. Recent projections show an increase in wave heights and periods along much of the Indian coast, with maximum wave heights increasing by more than 30% in some locations. At most locations along the east coast, wave periods are expected to increase by almost 20%, whereas along the west coast an increase of around 10% is expected. Similarly, water elevation due to cyclone activity is expected to increase.
  • Approximately 64 million people live in low elevated coastal areas that are less than 10 meters above sea level. These areas are exposed to both coastal erosion and storm surges, with the highest exposure found on the east coast of India. Most of the people in low lying coastal areas are concentrated in the Ganges Delta, one third of which is within the Indian territory, including the city of Kolkata which is home to 4.5 million people.
  • With a growing coastal economy and an increasing population in coastal areas, India has been managing recent coastal risks with large scale investments aimed at protecting infrastructure, with numerous programs dealing with coastal risk management.
  • Under a medium emissions scenario, the population exposed to the annual coastal flood level is expected to increase from 17 million to 21 million by 2050.
  • With a population of 1.37 billion people, India is one of the most populous countries in the world. Given its large spatial distribution and agro-ecosystem diversity, several farming systems exist with a significant cultivation of rice, wheat, sugarcane, vegetables and fruit trees.
  • Whereas agricultural contribution to national GDP has declined over the last decades, a large share of the population still depends on agriculture for its subsistence. Irrigation schemes are still expanding to enhance food security. In fact, over 14% of India’s population is thought to be undernourished. Agriculture adsorbs over 90% of total water withdrawal in a country with high stress on water resources, raising severe sustainability issues if it is to sustain further irrigation development and cope with climate risks.
  • India’s urbanization rate is expected to grow from 35% in 2020 to more than 50% in 2050. Migration from rural areas due to climate impacts is expected to contribute substantially to this increase in urban population.
  • Smaller urban areas with less than 300,000 inhabitants have a predominant role in terms of share of the urban population. However, megacities with more than 10 million inhabitants are home to one-fifth of the urban population. Urbanization rates are growing rapidly, and urban areas are growing faster than rural areas. India’s urban population is expected to grow from 340 million in 2008 to 590 million by 2030, an increasing trend which is expected to continue until 2050 in all types of cities, but in particular in megacities.
  • Built-up areas cover 2.27% of India (67,385.25 square kilometers).
  • The current (2019) energy mix of total primary energy supply in India is dominated by coal (45%), oil (25.6%) and biofuels (20%). Natural gas accounted for 5.7% of total primary energy supply and hydro, solar and wind together accounted for 2.5%. India is dependent on imports for both coal and oil. Despite having rich coal reserves, domestic production cannot keep pace with demand. A lack of domestic oil reserves leaves India highly reliant on crude oil imports.
  • India ranks 7th in terms of GDP in the G20 group, with one of the largest growth rates. Due to COVID, for the entire 2020/21 financial year, the overall rate of contraction in India was, in real terms 7.3%.
  • The agricultural sector in India is particularly vulnerable to the effects of climate change such as increasing temperatures and variability in rainfall. This will have significant repercussions for the Indian economy and the country’s food security that relies mostly on domestic production to meet the needs of a growing population.
  • In particular, declines are projected for rice and wheat yields due to climate change, with economic losses by the mid-century between 43 and 81 billion EUR (or 1.8-3.4% of GDP).
  • This is also expected to have substantial effects on Indian farmers’ income. It is estimated that in the absence of any adaptation measure, climate change could decrease average farm incomes by 15%, peaking at 25% for unirrigated areas, by the end of the century.

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