As the Center for Climate and Security’s Senior Fellow for the Indo-Pacific, I recently participated in a three-day conference hosted by the Hollings Center for International Dialogue that delved into the challenges and opportunities of the world’s megacities. Held in Jakarta, one of the largest megacities in the world, the conference brought together more than 20 experts from around the globe to explore key thematic issues of sustainability, climate and energy resiliency, the food-water nexus, social and governance issues, as well as concepts of rejuvenation and heritage preservation.
As defined by the UN, megacities are urban agglomerations exceeding 10 million inhabitants; currently there are 47 megacities, of which more than 30 are in Asia alone. Since 2007, more people now live in cities than in rural areas, with projections that this will increase to almost 70% by 2050.
An important discussion thread was the janus-faced nature of megacities with regard to climate change.
On the one hand, megacities are possibly one of the largest—if not the largest—‘single’ contributor to global emissions. Case in point, more than 70% of global CO2 emissions are emitted from cities; with NASA describing megacities as the largest human contribution to climate change.
Notwithstanding, the conference brought into sharp relief the specific challenge climate change poses for megacities.
Foremost is the risk to infrastructure due to sea-level rise, inundation, and coastal flooding. In broad terms, a combination of these factors could amount to $1 trillion in infrastructure damages by mid-century under a 0.5m rise scenario.
As is the case, climate change is one of a myriad of issues facing megacities. Using Jakarta as an example, the over-extraction of groundwater combined with sheer weight of that cities built infrastructure is seeing parts of northern Jakarta sink at up to 15cm per year. Some estimates have 95% of north Jakarta underwater by 2050. In combination with sea-level rise and other factors, there is even talk of relocating the capital. A USD $40 Billion sea-wall known as the National Capital Integrated Coastal Development is also being seriously considered.
Sea-level rise can have a disproportionate impact on megacities located around the equatorial region—not just because of contributions from melting ice and glacial run-off—but also due to the thermal expansion properties of water. Asian megacities are especially at risk in this respect.
Climate change is also disrupting major global climatic systems such as El Nino, Indian Ocean Dipole and Southern Annular Mode; altering rainfall patterns, glacial formation and melt, and monsoon patterns (to name a few). Changes to rainfall patterns in combination with historical drought, heat waves, coastal erosion, flooding, poor land-use practice, salinity, crop failure, and natural disasters are all key factors driving rural to urban migration and contributing to the unimpeded growth of megacities.
A 2018 World Bank report noted that by 2050 more than 140 million people could be forced to migrate as a result of the slow onset of climate change. In megacities, people often locate to slum areas where, despite economic opportunity, life can be fraught with extreme poverty, public health hazards, and human security risks such as trafficking, exploitation, and lack of access to basic water and sanitation services. Mass movement (either internal or transboundary) can also disrupt existing social orders, leading to instability, violence, and (in extremis) warfare and regional chaos.
Syria continues to serve as an unimaginably devastating example of the destruction and misery that can be unleashed once societal breaking points are crossed. Like a climate tipping point, there can often be no return.
The Hollings Center Dialogue Conference shone a much-needed light on some of these issues. It also established a foothold for future dialogue sessions, particularly with regard to advancing our collective understanding of how climate change will impact megacities from a human-security perspective.