Climate change is transforming aquatic ecosystems. Coastal waters have experienced progressive warming, acidification, and deoxygenation that will intensify this century. At the same time, there is a scientific consensus that the public health, recreation, tourism, fishery, aquaculture, and ecosystem impacts from harmful algal blooms (HABs) have all increased over the past several decades. The extent to which climate change is intensifying these HABs is not fully clear, but there has been a wealth of research on this topic this century alone. Indeed, the United Nations' Intergovernmental Panel on Climate Change's (IPCC) Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC) approved in September 2019 was the first IPCC report to directly link HABs to climate change. In the Summary for Policy Makers, the report made the following declarations with “high confidence”:

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Harmful algal blooms display range expansion and increased frequency in coastal areas since the 1980s in response to both climatic and non-climatic drivers such as increased riverine nutrients run-off.

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The observed trends in harmful algal blooms are attributed partly to the effects of ocean warming, marine heatwaves, oxygen loss, eutrophication and pollution.

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Harmful algal blooms have had negative impacts on food security, tourism, local economy, and human health.

In addition, the report specifically outlines a series of linkages between heat waves and HABs. These statements about HABs and climate change and the high levels of confidence ascribed to them provides clear evidence that the field of HABs and climate change has matured and has, perhaps, reached a first plateau of certainty. While there are well-documented global trends in HABs being promoted by human activity, including climate change, individual events are driven by local, regional, and global drivers, making it critical to carefully evaluate the conditions and responses at appropriate scales. It is within this context that the first Special Issue on Climate Change and Harmful Algal Blooms is published in Harmful Algae.

气候变化正在改变水生生态系统。沿海水域经历了逐渐变暖，酸化和脱氧的过程，这将在本世纪加剧这一趋势。同时，科学共识认为，有害藻华（HAB）对公共健康，娱乐，旅游，渔业，水产养殖和生态系统的影响在过去几十年中都在增加。气候变化加剧这些HAB的程度尚不完全清楚，但仅在本世纪，就此主题进行了大量研究。实际上，2019年9月批准的联合国政府间气候变化专门委员会（IPCC）关于气候变化中海洋和冰冻圈的特别报告（SROCC）是IPCC的第一份直接将HAB与气候变化联系起来的报告。在“决策者摘要”中，

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自1980年代以来，沿海地区的有害藻华显示出范围扩大和频率增加，这是对气候和非气候驱动因素（例如增加的河流养分径流）的反应。

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观察到的有害藻华的趋势部分归因于海洋变暖，海洋热浪，氧气流失，富营养化和污染的影响。

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有害的藻华对粮食安全，旅游业，当地经济和人类健康产生了负面影响。

此外，该报告特别概述了热波与HAB之间的一系列联系。这些有关HAB和气候变化以及它们所具有的高度信心的陈述清楚地证明了HAB和气候变化领域已经成熟，也许已经达到了确定的第一个平稳阶段。尽管人类活动（包括气候变化）推动着HAB的全球发展趋势有据可查，但个别事件是由地方，区域和全球驱动因素驱动的，因此至关重要的是仔细评估适当规模的条件和应对措施。正是在这种背景下，《有害藻类》出版了第一期《气候变化与有害藻类绽放》特刊。