Dramatic climate changes and weather extremes are already affecting millions of people around the world, damaging crops and coastlines and putting water security at risk.

Across the three regions studied in this report, record-breaking temperatures are occurring more frequently, rainfall has increased in intensity in some places, while drought-prone regions like the Mediterranean are getting dryer. A significant increase in tropical North Atlantic cyclone activity is affecting the Caribbean and Central America.

There is growing evidence that warming close to 1.5°C above pre-industrial levels is locked-in to the Earth’s atmospheric system due to past and predicted emissions of greenhouse gases, and climate change impacts such as extreme heat events may now be unavoidable.

As the planet warms, climatic conditions, heat and other weather extremes which occur once in hundreds of years, if ever, and considered highly unusual or unprecedented today would become the “new climate normal” as we approach 4°C—a frightening world of increased risks and global instability.

The consequences for development would be severe as crop yields decline, water resources change, diseases move into new ranges, and sea levels rise. Ending poverty, increasing global prosperity and reducing global inequality, already difficult, will be much harder with 2°C warming, but at 4°C there is serious doubt whether these goals can be achieved at all.

For this report, the third in the Turn Down the Heat series, we turned again to the scientists at the Potsdam Institute for Climate Impact Research and Climate Analytics. We asked them to look at the likely impacts of present day (0.8°C), 2°C and 4°C warming on agricultural production, water resources, cities and ecosystems across Latin America and the Caribbean, Middle East and North Africa, and parts of Europe and Central Asia.

Their findings are alarming.

In Latin America and the Caribbean, heat extremes and changing precipitation patterns will have adverse effects on agricultural productivity, hydrological regimes and biodiversity. In Brazil, at 2°C warming, crop yields could decrease by up to 70 percent for soybean and up to 50 percent for wheat. Ocean acidification, sea level rise, tropical cyclones and temperature changes will negatively impact coastal livelihoods, tourism, health and food and water security, particularly in the Caribbean. Melting glaciers would be a hazard for Andean cities.

In the Middle East and North Africa, a large increase in heat-waves combined with warmer average temperatures will put intense pressure on already scarce water resources with major consequences for regional food security. Crop yields could decrease by up to 30 percent at 1.5–2°C and by almost 60 percent at 3–4°C.

At the same time, migration and climate-related pressure on resources might increase the risk of conflict. In the Western Balkans and Central Asia, reduced water availability in some places becomes a threat as temperatures rise toward 4°C. Melting glaciers in Central Asia and shifts in the timing of water flows will lead to less water resources in summer months and high risks of torrential floods. In the Balkans, a higher risk of drought results in potential declines for crop yields, urban health, and energy generation. In Macedonia, yield losses are projected of up to 50 percent for maize, wheat, vegetables and grapes at 2°C warming. In northern Russia, forest dieback and thawing of permafrost threaten to amplify global warming as stored carbon and methane are released into the atmosphere, giving rise to a self-amplifying feedback loop.

Turn Down the Heat: What Climate Change Means for Latin America,

Turn Down the Heat: Confronting the New Climate Normal builds on our 2012 report, which concluded the world would warm by 4°C by the end of this century with devastating consequences if we did not take concerted action now. It complements our 2013 report that looked at the potential risks to development under different warming scenarios in Sub-Saharan Africa, South East Asia and South Asia, and which warned that we could experience a 2°C world in our lifetime.

Many of the worst projected climate impacts outlined in this latest report could still be avoided by holding warming below 2°C. But, this will require substantial technological, economic, institutional and behavioral change. It will require leadership at every level of society.

Today the scientific evidence is overwhelming, and it’s clear that we cannot continue down the current path of unchecked, growing emissions. The good news is that there is a growing consensus on what it will take to make changes to the unsustainable path we are currently on.

More and more voices are arguing that is possible to grow greener without necessarily growing slower. Today, we know that action is urgently needed on climate change, but it does not have to come at the expense of economic growth. We need smart policy choices that stimulate a shift to clean public transport and energy efficiency in factories, buildings and appliances can achieve both growth and climate benefits.

This last report in the Turn Down the Heat series comes at a critical moment. Earlier this year, the UN Secretary General’s Climate Summit unleased a new wave of optimism. But our reports make clear that time is of the essence.

Governments will gather first in Lima and then Paris for critical negotiations on a new climate treaty. Inside and outside of the conference halls, global leaders will need to take difficult decisions that will require, in some instances, short term sacrifice but ultimately lead to long term gains for all.

At the World Bank Group we will use our financial capacity to help tackle climate change. We will innovate and bring forward new financial instruments. We will use our knowledge and our convening power. We will use our evidence and data to advocate and persuade. In short, we will do everything we can to help countries and communities build resilience and adapt to the climate impacts already being felt today and ensure that finance flows to where it is most needed.

Our response to the challenge of climate change will define the legacy of our generation. The stakes have never been higher.

Author: Jim Yong Kim is President of the World Bank Group.

Image: The hand of a villager of Mourisia is seen as he looks at a forest fire in the Acor’s mountain range in Arganil. REUTERS/Nacho Doce